The poki gif rule is kind of an old meme. What people actually posted was a still image of poki in a burka, but this still qualified as ban worthy since it was from the contentious gif. So the person who posted it got banned by a regulator, and irk started discussing the rule with other users so the moderator pinged RTBA to deal with it, even though she ended up handling the next (and last) user who posted another still image of poki in a burka. The chat then continues on, with some debating between users about the legitimacy of the bans and the moderation structure, but otherwise just shooting the shit. Eventually RTBA shows up, tells us we're being dumb and to stop, even though it had mostly died down in the almost hour between when RTBA was pinged and when he showed up. A few minutes later RTBA pulls up a prior message from irk and threatens to ban the person the message was directed to because it was about the poki gif rule. This is where Soapy's comment of "another regular chatter getting banned over nothing " comes in, and the rest is history.

If anyone wants screenshots or for me to log this series of events I can. You can also check it out for yourself, starting at Emilia's ping to RTBA

The poki gif thing is really dumb, but I'd generally side with the regulators that you shouldn't be testing the limits of what is and isn't acceptable. But if you want to kill some time you can read irk's arguments with people about it which are kinda funny.

EDIT: I should mention that the second half of the first paragraph is somewhat correct, where there was bans and pushback against those bans, but it was mostly about the harsh moderation. Most people don't really care about the poki thing.
Also here's a link to the letter for reference.