Nothing has changed recently. There have been dozens (probably hundreds) of discussions about feminism on HN. Some stay on the front page; many don't. As with any divisive topic that comes up frequently, the threads tend quickly to become flamewars, and those tend not to stay on the HN front page, though the discussions stay open for additional comments.
Many things affect a story's rank. Upvotes make it go up. User flags make it go down. Moderators downweight posts for various reasons (e.g. when a story or thread breaks the site guidelines or has been discussed recently). Software downweights posts for various reasons. Sometimes it's all of the above.
Please follow the guidelines and send this kind of question to hn@ycombinator.com, rather than posting it on HN itself, where it's largely off topic.