As for the "only keeping babies that are perfect" thing? Honestly, no one gets the child they imagined, absolutely no one because they're individuals and you can't make them be who you imagined they would be. However you can have basic expectations that they will develop in a typical way, will be reasonably healthy, will mature, and will go off into the world to live their own lives. Having a disabled child changes that. You don't know how your child is going to develop, whether their development will continue but at a slower pace, whether it will be more or less typical, or whether it will halt. You don't know if they will be healthy and if they aren't healthy you don't know whether they will be able to access treatment, let you know they're unwell, whether they will have a decent quality of life due to treatment, and so on. You don't know if they'll ever be wholly independent or independent at all and if they're not independent you don't know what will happen to them when you're gone - not just who will take care of them but who will love them, who will spend time with them, who will want them. You can't think too much about the future because therein lies sleepless nights, that tight chested feeling, and the anxiety spiral. You worry about your other DC and whether they're missing out, whether they resent the situation, whether they're getting enough time and attention. You worry the same about your disabled DC. You have appointments, meetings at school, EHCPs to organise, DLA/PIP reviews just in case your child was miraculously cured of their life long condition, support to fight for, professionals who will look you in the face and say you don't need help when you clearly do, you have to constantly advocate, constantly fight. It affects your marriage your friendships and other relationships, your ability to work, your social life, your own health. It's not a situation that should be forced onto anyone and at the centre of it is a child that you are hoping you are doing right by.
I love my children but if I knew then what I know now, I don't know if I'd have continued the pregnancy. Their disabilities certainly influenced our decision not to have any more children as we didn't want to risk another child with the same difficulties.
If that makes me worse than Hitler then I guess I'm Hitler 2.0 - fucking hiel, me.