I don't know if I'm aware of all the issues. I just notified about the Bad Pun Dog meme calling people "right-wing, racist, pro-life," and the KKK picture, and also told what action I'd taken. Here's what I wrote (copied and pasted together from several comments):
"There's a user named "Pazuzu" who has been making memes against people on the leaderboard. I think we may need your help, if that's possible (and if you think it's called for).
I'll post links to some of the memes shortly.
Here is a meme where he accused people on the leaderboard of being "right-wing, racist, pro-life"
imgflip.com/i/v31ke
and another meme where he compared imgflip's leaderboard to the KKK
imgflip.com/i/v0ljc
Aside from replies on these and other similar memes, the other action I have taken is:
I've written a note on one of his earlier memes, asking him to stop, and
I've flagged recent memes in the comment stream about me (made anonymously, but I'm treating them as if they're made by Pazuzu until I know otherwise) for abuse of the terms of service of imgflip, so the mods can take a look at them.
Thanks so much for taking a look at this. I really appreciate your time. If you think it's not serious enough to be worth the trouble, please just let me know.
Also please let me know if you have any other questions about it or need other info. Thanks again."
(But I still haven't heard back yet. I don't think it would hurt if you contacted K also. Hope that helps.)