What makes you say that? In my experience, the spam button works fantastically. There is a gym of some kind that has me on their mailing list, refuses to honor unsubscribe, and sends me probably 2-6 emails a month. They've been doing this for years, but Google correctly gets every single one into spam because I marked one (several?) as spam years ago.
Most, if not all, political junk email also ends up in my spam folder after judicious use of the spam button a few years ago.
Most, if not all, political junk email also ends up in my spam folder after judicious use of the spam button a few years ago.