Here are some things (assumptions maybe?) that would set-off some internet shitweasels. Stuff I noticed just about this post.
So at age 27 I started playing singleplayer games on Steam.
Not an experienced gamer, nothing wrong with that...
At age 28 (now) I finally worked up the nerve to get back into TF2, which I played maybe 2 hours of years ago before giving up due to utter intimidation.
Being intimidated, or scared to play games online anonymously. Personally I think that is a bit silly, I've never looked at games this way. They are made for everyone who cares what the community things.
I was told multiple times by friends who know I'm feministy ... that CS:GO was one of the most toxic communities out there even for a casual player.
You are warned about the toxic community, adding to your fears of being preyed upon because you're a woman. Insert the generic toxic misogynistic gamer stereotype spiel here, men are bad, etc.
Stream w/ me on Twitch (I keep my clothes on, put your pitchforks away pls)
Self-admittedly you're not an amazing gamer with amazing skills. It doesn't sound like you do anything really special when you game, aside from game. You've explained that you're hesitant to enter gaming scenes with toxic communities but... You have no issues streaming to Twitch? What do you bring to Twitch?
Why exactly do you stream to Twitch then? I bet that even though you aren't an amazing gamer, you probably have more traffic on Twitch based on the sole fact that you're a woman. Nobody decides to go "Hey, I'll start a Twitch channel but just for me, I hope nobody else watches." so at some point you consciously chose to broadcast yourself for some sort of self-gratification.
This is what draws vitriol from angsty young males. You literally feed the "Teehee, look at me not-so-skilled girl gamer." role here.
I'm not trying to troll, bully, or antagonize you. Just giving you a wildly meta perspective into how something innocent that you may not have ever thought of adds fuel into the whole "Girls in online games" fire.