Ok hi I'm a huge fan of Adam (as a character, not really the movie) so here's my best answer to everything!
Totally agree. As an autistic person this movie can be hell to watch bc you know exactly what he's going through. It is so relatable in a way that hurts. Part of the reason I can't rewatch.
I've never head of anyone really defending her? In the movie people back her up bc it's her family and friends. Really, despite his name being the title, Beth is the center of the movie bc she's the one trying to "fix" him. He is mostly just there and reacting. Anyone who defends her is really just defending ableism unfortunately and that's where she gets support from anyone who watches it. It's literally just people who think autistic people should change to fit society and that a good neurotypical can teach them how.
Which leads exactly to the message. Unfortunately, the message is, autistic people can change to fit into society. That's it. All his conflicts come from his symptoms (meltdowns, inability to understand lies or non-literal speech, his strict food habits, his inability to understand how others feel, infodumping not wanting to go out, etc.). Each of these conflicts are given solutions by Beth, the neurotypical saviour figure (ex: the Alfredo as a substitute for Mac and Cheese, stopping him when he starts to infodump at the party and at the theater, telling him to get over the fact that she lied to him multiple times, explaining how the things he does makes her/others feel, explaining that the raccoons in the book don't need to make sense bc they're not real, making him go to the party and the restaurant and the theater). At the end of the movie, you see him accept that raccoons in books can talk bc it's fiction, you see him choose to go out with people from work, you see he has accepted change and is happy. This is showing that he took into account what Beth said and changed (well really he's masking as anyone who really knows about autism would know, but yk the movie doesn't know that). He seems more neurotypical now. He's normal and happy for it. Unfortunately, this is one of the most common themes in media surrounding an autistic person.
It's a romcom bc the story centers around a romance. Especially so bc it's one of those "we have to learn things to be together" type movies. But yeah the relationship sucks and it's not funny. I don't think "romcom" is a literal label (or at least in my experience? But I'm not that familiar with the genre so)
I completely understand! You can love the character but hate the movie and what it stands for. That's where I am. He's so incredibly relatable and for a pretty ableist movie, he's actually extremely accurate in his portrayal of autism which I have to commend the writers for to some degree (as well as the fantastic Hugh Dancy <3). I can't not love and appreciate him for that.
He's labeled as selfish for a few reasons. Firstly, he admits that he struggles to know what others are feeling. He feels a certain way in a situation/time and projects that on to everyone everyone else in that situation/time (this is explained in the scene where he asks Beth if she is sexually aroused). This, especially to those who don't understand, can be twisted as being selfish. Some people would take this as only thinking about how you feel instead of how others feel, instead of recognizing that it is something he is actually unable to do because his mind does not work that way. Another thing is often times non-disabled people will see accommodations or other needs that come along with a disability as selfish, especially those that are set by the disabled person, and even more so for invisible disabilities (which includes mental/neurological conditions as well, which exacerbates that treatment further. This is because not just stigma around these conditions, but it's much easier to dismiss as it is not as obvious to see). Adam tries to accommodate himself. He says he doesn't like to break his schedule. He says he doesn't want to go to all those places and talk to people. He says he won't eat things that aren't his safe food. And yes, he does it because that's what works for him. Because that is what he needs. Unfortunately, in an ableist world, saying you need accommodations, when they want you to act neurotypical, is seen as selfish. Because that means that you're not confirming to their standards. Because they have to change what they are doing for you. And it doesn't help that he cannot see that people don't like him asking them to accommodate him. So no, he's not selfish. He's just autistic. But unfortunately, the ableists are too selfish to accommodate him or understand him so he's given that label instead.
Hope that helps!! I am always happy to talk about him so