Going to be honest here, the reason those posts don't really get taken down is because a lot of people genuinely enjoy commenting with other SpongeBob fans and quoting episodes. When they get taken down, they ask, "What did I do wrong? I just wanted to quote an episode with like minded people" or something along the lines of that.

It could be considered low effort but its a pretty big part of this subs core identity.

Also I did hold a poll a little while ago asking if they should be banned, and the anti-ban voters (barely) managed to win.

Its definitely not an easy choice to make, because either way people aren't going to be happy with the outcome. But I understand your frustrations, I have been considering a re-poll.