A lack of manners that women experience more than men

Isn't it also the implication of the comment she's responding to?

"I wonder why men see me as a sex object" > This implies that men do objectify women on Twitch, just that it's their fault for putting on clothes that are too revealing.

And you're right, the main issue isn't attraction, it's the objectification, ie unwarranted comments. And those comments aren't just the result of revealing clothes, because there's a moral agent typing them. And it's that person's responsibility to behave, even if they're attracted to someone who shows a bit of skin.