This is an insane amount of overreaction for something that was over before it started according to the ModDB terms of service. Anego Studios isn't indemnified here; the user accepts the risk of any third-party mod that was run. Maltiez did very clearly break the rules for mod uploads, and he was appropriately banned from the ModDB (and the Discord).
https://mods.vintagestory.at/terms
The fact that the studio made a response, addressed the concerns and offered refunds is above and beyond.
That said, I don't care for the fact that the development team was apparently aware of the "extra features" in Maltiez' mods before banning him from the ModDB. I think this should've been escalated as soon as he announced it to them. Self-righteous vigilantism isn't a good look, nor the right temperament for employed programmers. Ultimately, his continuing employment is up to Anego Studios; we don't know what conversations have been had or are ongoing internally, and we won't going forward. I don't really think browbeating them about the failure is productive or elucidating.