It's a little more than just an humorous remark (EDIT: not that I'm assuming he would actually archive the cases); the original text seems much more hateful. The last part of the post is roughly:

Shitty petistas¹. Motherfuckers. (...) I miss the time when this kind of thing was resolved with rubber (sticks) on the backs of the cowards...

¹ Supporters of the Partido Trabalhista, as far as I can tell.

>"there are certain positions of power from which I do not appreciate joking."

Exactly how I feel.

And no way it was a joke, since he used bad words in the original post I haven't translated, which indicates he was really pissed off and writing fluently.

How is it possible for that to be taken as a humorous remark?