I wanted to wait to see if they would calm down as I don't like being heavy handed when it comes to moderation, and as you say the mute functions should let people moderate the feed to their own liking, but the amount of posts effectively made the feed only show one type of post unless people muted.

Yeah it was ridiculous! I muted the memes after I think like a day and a half of it crowding out the feed, and then yesterday i asked my followers if it was still going and it was?? Totally nuts.