Yeah, I'm not arguing abortion is bad. I'm saying that we should deeply consider the morality of choosing to do it in such cases, because people with Down Syndrome or autism or other such differences can totally lead reasonably healthy and happy lives.
Nowhere did I claim that it is reasonable to "judge a potential parent who decided to terminate a pregnancy because they were told it is unlikely their child will be born alive" (in fact, I'm Polish and am horrified at the new law recently passed in the country in which I was born, which specifically intends to do away with this specific act).
I think it's fine if you can't support another kid because you can't support another kid. I think it's fine if your kid won't live because your kid won't live.
But people with Down Syndrome and autism do live. And I think we should strongly consider the morality of the situation before going down that road. If someone is already struggling enough as it is keeping their lives together and finds out that this is the case, I would at least say it's more defensible than otherwise, because it is indeed harder to provide for some kids. But all kids are hard to provide for in their own way, and perhaps that person shouldn't be having kids anyway if that's the case. After all, we can't ever test for everything; it's entirely possible still to have a kid with something that can't be tested.
And people do discourage pregnant mothers from drinking, because that's an easy step to take to ensure higher chances of a happy and healthy baby. It's a false equivalence to compare that to terminating a potential life.
I won't judge people for their decisions. They have their reasons for doing what they'll do. And I'm absolutely unabashedly pro-choice. And of course I would have a hard time dealing with hearing that my kid will end up having Downs or whatever. But I think there is an aspect of morality to consider here, and the plain-and-simple "we should decrease the number of people born with Down Syndrome", presented without exception (as you put it, "absolutely"), does not fit my view. It's too close to eugenics for my taste.