>>42044776TL;DR version:
Magni lied about something which triggered some Karens into scolding him, which triggered him into clamming up about personal information for a while
Long version:
Right when Vesper got suspended, Magni broke his back and also caught COVID. He lied and said COVID was just a cold for the following reasons: still wanted to stream, didn't want to potentially be forced into a vacation by management/Cover, didn't want to be out at the same time as Vesper and have even fewer streams for viewers and generate more rumors. (In retrospect, he says he probably should have just taken it easy.)
After he got over COVID, he casually admitted it onstream and laughed it off, which made a minority of viewers unreasonably upset. A small group of fans circlejerked about it on a private Discord and all agreed to dump essays in Magni's comment section about how unacceptable his behavior is, how they can't support that and are cancelling their memberships, etc. They listed various reasons but the common thread was them feeling deeply betrayed that he lied. (I personally suspect they were yumeing too hard and projected some cheating ex-BF trauma onto him, considering how over-the-top emotional they got when it wasn't a big deal).
Hours later, he posted in membership that he was being way too open about his private life and said he'd stop oversharing. For a while afterward (maybe a couple weeks?) he acted cagey onstream and would cut himself off with "nevermind" once he started veering into personal information territory.
We got pissed off that this small number of idiots from some Discord somewhere ruined it for everyone else, so that disgusted Magmite image started being posted in reference to those people, any time Magni backpedaled on personal information, or in reaction to new Karenish comments (e.g. getting upset about Magni's "commit sudoku" intrusive thought -> Sudokumite edit)