Yeah, it's a topic I used to post about a lot because even talking to people has been hard for me at some points in my life. My 20's have been the hardest of all, since I pretty much have always failed at making friends in the workplace or through places like meetup groups. At my first job I was so busy trying to keep up that it felt like a conversation would just piss off my manager. So everyone else would talk while I'd just be there.
I've found a couple online circles I like through gaming, and am trying to find other regular writers in my genre.
Some of it is just location. It's always a roll of a the dice whether or not someone has the right personality or values to mesh well with a group, and how open-minded people are. If you rub even one person the wrong way, they might make a stink until it's just easier to leave than to have them listening in for an opportunity to put you on the spot and make things uncomfortable.
Forums I think aren't really the best places to make friends as they're decreasing in popularity so much, this is just opinion. Discussions seem to be getting shorter and more heated over the years, as a lot of opinionated people go to them to air their dirty laundry, and others just come to vent. It feels like trying to make friends at a political rally sometimes.
I've also gotten very suspicious of forums as a place to meet people. If you're a woman, plenty skulk around with sob stories for sympathy. I've caught people lying about things like breakups to get attention and it's tainted the experience for me. Some days it seems like it's better to just assume everyone is lying.
Social media is like advertising, which I hate. It's all about posting the right content, at the right times, with the right phrasing to maximize the number of views and responses. Figuring out what people will hear that makes them want to say something. This is one of the reasons I decided I don't want to write professionally, as the authors who are making money are going out and spending massive amounts of time networking, promoting their work, etc.