When people feel insecure, some will go on the attack. I could go into a whole sociopolitical thing here but that would probably be inappropriate to this forum. Please remember that when they behave that way, it's about them, not you.

You're very wise to avoid those kinds of districts! There are so many risks, and listing them would become a novel-length post.

What you're facing is the local culture, not anything universal. There will always be people who judge, but it's their own insecurity that drives them. That applies to your extended family as well. They're your blood but they still have all the same foibles as those not related to you. You will fare better elsewhere, and keeping a mental barrier in place to protect you from family insult.

Woah, I never knew that about San Francisco, no wonder the culture is so awful! You'll do very well to get out of that nightmare. Just stay true to yourself until you can escape to a more suitable place. Even if no ASD support groups exist around there (though such a major city must have at least one), you have a path forward with your schooling. Focus on that, not what surrounds you.

Professional academics are no different from anybody else. Some are petty, looking down upon each other for specializing in a subject they view as "less than." Some hold onto rigid biases, or are hypocrites. For example, those who go to climate marches yet throw trash and recycling in the wrong bins on a daily basis and use Styrofoam cups for their coffee multiple times in a day. Yet some others are dedicated instructors and researchers. No group of any kind is a monolith.

I'm in southeast PA. It's a patchwork of mini-cultures around here. If you don't mind me saying, it sounds like your area really @@$%ing sucks. A good person can't be expected to thrive in an environment like that. I urge you again not to beat yourself up over it, and not to focus on it excessively. That will only harm your self-esteem and make you too focused on the negative. A lot of people, no matter where they stand in life, never actually grow up, they just grow older. That, unfortunately, is something that seems universal. In a new place where nobody knows you, there won't be gossip. You can get a totally fresh start.

STEM is overwhelmingly dominated by white heterosexual cisgendered males. Efforts to address this have had limited success. You are certainly not the only one to have put an academic career over a social life! No offense intended, but that's almost a cliche. Americans and Brits use the term "wonk." The Japanese use the term "otaku." It's common enough worldwide to have special names, so you most certainly are not alone in that regard!

I wish you the best in your studies. The medical profession is a noble one, so long as the doctor has empathy. I've known some awful ones, but also a few good ones. You will be one of the good ones. The higher percentage of women in your field is a good sign of hope! Most of them will also be likely to have put off the dating scene to focus on their careers. And you'll be alongside people with shared values and goals. Your current environment is full of those who are selfish and shallow. What you'll find in medical school should be completely different. Be prepared for meeting some who are there because of the money and status, or because their parents pushed them there, but just as many if not more will be there because like you, they want to help people become well.