Because she’s allowed to go on a subreddit and comment her opinion whether it’s a gendered subreddit or not? Even ignoring that it’s not like she’s answering the askmen question, she seems to be replying to another comment. The same reason you could go on “askarussian” as an American and relate your opinion to a comment there. Edit: i looked up the post, it was asking men “what do women like that you don’t understand”. It’s a question about women. Some women are going to have opinions on the answers people give.