No - no one KNOWS that their child is a monster. Because their child isn't a monster. All bio parents have blind spots, but I think my SO knows most of the areas where his kids have problematic behaviour. Just as I know most of the areas where my son has problematic behaviours. Sometimes, it helps to have another perspective. If you are parenting a minor child and your partner refuses to see where there's a problem whether for you or any other person in the household you have a partner that encourages bad behaviour. 

I had to have a heart to heart with my SO about my OSSs super selfish behaviour, but he saw it. Why wouldn't that kid be selfish - one he's a young teen, but also he's been raised by a super entitled BM who has taught him to be super entitled. OSS doesn't even think he's being selfish, because he does care about others and their feelings. But he did see it after we spoke and while we can't always prevent it we can deal with it. 

Yeah parents have blind spots and as an outsider stepparents see it. All we can hope to do is gently call attention to their monster like behavior. For example SD when she was 3 to 5 yo was intentionally hurting my dogs. At first I thought ok 3 needs help playing nice with the dogs but when she was correctly she'd give an evil grin make eye contact and pinch or hit the dog.  SO first said she was just little and had an elder dog with bm who didn't care. She would pinch, poke, hit, and sometimes choke a dog until they coughed and struggled giggling the whole time. It wasn't until I filmed multiple incidents of her hurting the dogs and laughing or intentionally doing it again when I corrected her that SO finally got his head out of his butt. 

No, they don't know, and not only do they not know, they rufuse to acknowledge even in the slightest that they're kid is a monster.

So we have two choices, right? We can either not give a damn and live our lives ignoring their children (which makes us "monsters" in their eyes), or we can give up our lives and well being to take over parenting of a spermstain that probably should have been flushed down the toilet. (That was harsh, I get worked up when this topic comes up. My estranged wife bred with a complete loser, and held her kid in a higher esteem than our shared child, and proceeded to fault me for not "bein a dad" to her little ball of ADHD.) Just think if you had to live with that child 6/7 days a week. It's complete hell.

It's lose/lose ever getting with a person that has crotchlets from another relationship. Personally, I plan to not even consider getting into another relationship until long after my daughter launches and is self-sufficient.

Boy, things have changed since I was a kid. Back then, there was discipline and we knew we had to respect our parents or else we got the belt

Now, kids are kings and queens of the household and parents walk around them as if walking on eggshells.

My BF son does whatever he feels like all the time, that includes bad mouthing and being disrespectfull. I ask him to fill the dishwasher the other day. He started to do it but halfway thru, he just decided he didn't want to do it anymore and just stop and went back to his xbox. When I mentionned it to him, he took a big sigh, looked at me with those evil eye, got up pissed off and basically threw the remaining dishes in the dishwasher, breaking a boll in the process. 

But he's soooo precious !!!

(Yeah.... right)

My DH is VERY aware of his daughters issues. The sentence "BM created this monster" comes out of his mouth a lot. While he still looks for little glimpses that she is his sweet little girl he is by no means blind to the reality.

I love my DW with all my heart but in many cases (no blanket statement here) Bio Parents are either too scared of losing affection or maybe it is some viral infection they get.  In any case, I think many are at least marginally aware but society is now screaming at them that the all important children cannot be corrected.  After all, they are just like those kids on the commercials who are so wise while the parents are Neanderthals. 

Seriously, I believe that Bios struggle with a variety of pressures from alienation of affection to the stark look in the mirror to say omg I am not helping my child by letting them be this way.  Personally, I am sock to my stomach over the societal change to the messiah children who can do no wrong. 

Suggestion:   WATCH MEDEA MOVIES AND EMULATE. 

Sometimes my DH isn’t in denial but most of the times he is. 

The best was when he was going on about the neighbor’s 20-something yo kid who we nicknamed Jersey ( short for Jersey Shore). DH was commenting about his crap attitude, how he cranks his stereo in his car and peels out of the crescent at  Mach 1, his stupid hair cut (shaved sides and a top knot), and his jeans that are worn low and show his underwear. DH hates that kid. I pointed out over that a Jersey is the spitting image of skid24. Same hair cut, attitude, does the same stupid peel out of the crescent with the tunes cranked when he is pissy ( which is most of the time), they even have the same short stalky build. The light bulb went off in DH’s head. He complains a lot less about the neighbor’s kid now lol.

if they keep believing their little or adult devils are in fact angels, that the magical universe will turn them into angels

"They're smart arsses, but they are just joking." 

The thing is, nobody is laughing and the barage of insults, is anything but humorous. One excuse after another; so inappropriate behavior escalates.

They know it, but they excuse it--- because they are weak daddeees who refuse to correct it.

I think they do know especially when their kids poor behavior is extreme. When I was first getting to know my now ex, he tried to make it seem like his youngest adult daughter was some sort of saint. When an issue came up that was a source of stress for him I tried to let him know politely that his daughter wasn't being honest with him. He said "My daughter doesn't lie." I'm thinking to myself oh she is definitely telling you lies but I figured he would find out sooner or later. As time went on she lied more and more, apparently started forging documents, became more manipulative, and even became more disrespectful. What I didn't know was that she verbally abused him and that he is obviously afraid of her. So much that he tries to buy her love no matter how poorly she treats him. The day she called and disrespected him and our relationship and verbally abused him, I knew this had been going on for a long time and that he had been hiding it from me. My friends and family agree. That day she acted out like that I set him straight on exactly what type of person his daughter really is and how his failure to discipline her contributed to her turning out to be the very type of woman he claimed to not like. He looked like he was going to cry. He knows that with him I come from a place of love so Im sure he knew I wasn't saying the things to him I did to hurt him, but I said them out of love and truth. That day I broke up with him. I'm certain he already knew his daughter was screwed up. Thinking back I remember him even saying something like he hoped his love for her would make her into a better person because he wanted her to be just like me. At one point he was even trying to force responsibility of her off on me. Like he was looking for me to be a mom to her and she is 24 years old. No way in hell was I going to allow him to put that problem adult kid off on me. 

Dipshits are blind to reality.  Oh, they know. But they would go down in flames rather than admit that their spawn are monsters.  Their blindness is a choice.

Saw this the other day ...

"My Children are Angels" ....... answering:   "So was Lucifer"