Someone on HN complained that this wasn’t available, so now it is. Visitors not logged in will now see the filters link at the top. Filtered out tags are saved in a long-lasting cookie, rather than in their user record as with logged-in users.
I added tag filters to this site because I wanted them to filter out stories about programming languages I don’t use, but since I have to moderate everything here, I can’t filter anything out. Woe is me!