i'm more interested in hearing your reason for making this thread. you have said "why", but i'm wondering if anything has happened or may be on your mind other than what you've said--if not, disregard this, it's not a "why are you making moral highground threads"/attack, just genuine curiosity.
as far as answering your question... no i don't think they're "funny" in the way that i get some sort of enjoyment out of the condition they were born into. i think the reason others enter into that sort of behavior has more to do with how they view themselves more than it does with whatever fault they find in others--it's just masked behind fault in others in order to keep certain truths from being brought into conscious awareness. at least that's what i get from the reading i get from the people who do this sort of thing... although, you may have a point in the "learned-behavior-department".
when it comes down to it... what are you going to do in situations like that? i'd personally like to take them aside and physically hurt them until their little "shield" comes down and then start in with the mental and emotional pain they cause others, but laws are frown on that sort of thing; plus you risk detriment to yourself. or, you can speak to them about the real damage they're doing, but then you'll come off as some walking PSA-announcement/"after-school-special" which anyone immature enough to act in this way to begin with... well, whatever you say will go straight over their heads anyhow.
i personally think they're cute, not like in a "dog is cute" way, but as in a "child is cute" way; they are innocent and they are pure. my girlfriend is in nursing school and had an odd form of clinicals in which she took kids with downs syndrome bowling. she said she's never met a person who could enjoy life as much as those kids did--everything was wonderful to them... then i look at myself and in comparison, i'm lacking severly in ways in which they excell, such as enjoying my own existence.
they're cute in a good way, they're funny-looking in a non-offensive way, and i like Psuedo feel more uncomfortable with how i can potentially make them and their family feel more so than any discomfort i feel upon seeing them.