One can try to visit tech websites, or even tech offices. I am a woman, and I'm often left with a feeling of being 'the other', sometimes unfavourably so. The most obvious cause is that it is often a community of mostly men discussing both male and female characteristics. A more subtle clue is that it seems that they refer to women as "females", but men as simply "men". Some communities are even hostile to the idea of feminists - in turn some feminists forego speaking up about their feelings, and pretending to be "just another bro".
One crucial difference is, of course, that feminists only talk about gender and things that are related to that. Tech-communities might sometimes talk about gender, but most might only talk about it when it is somewhat relevant to their tech-interests. Feminists, on the other hand, have a practical monopoly on gender-opinions as far as mainstream opinion is concerned. And they're mostly women, and might even reject men into their circles. Programmers being mostly men might bias things like technological choices, but the bias towards women in gender-theory (might as well say feminist-theory) doesn't change a niche thing such as what programming language powers the client-side web, it heavily influences popular opinion on what men are and what they should be like, even though they are not really a represented group. That might not be a problem if some vocal feminists didn't try to work against alternative paradigms of gender theory, but in my experience, they do.
Your last point would be more analogous to my own if you said that some communities are even hostile to the idea of women programmers (if that is indeed true).
Another crucial difference is that you can easily choose to not read and participate in feminist blogs and communities, whereas I have to interact with tech communities every single day. Reading tech websites is crucial to my career, and well, I gotta go to the office every day too.
I work at a top tech company in Silicon Valley, in a team of 200 men and 10 women. The men aren't intentionally hostile towards me at all, but they are blissfully ignorant of how their comments and behavior genuinely makes it hard for the few women around them to succeed and be considered equals.
One can try to visit tech websites, or even tech offices. I am a woman, and I'm often left with a feeling of being 'the other', sometimes unfavourably so. The most obvious cause is that it is often a community of mostly men discussing both male and female characteristics. A more subtle clue is that it seems that they refer to women as "females", but men as simply "men". Some communities are even hostile to the idea of feminists - in turn some feminists forego speaking up about their feelings, and pretending to be "just another bro".