Utterly Mad

Okay, let me rephrase and reword myself
In my opinion, there is nothing wrong if a mod author asks for donations. In my opinion unless you have permission from the developer you are not allowed to SELL the mod, and this goes for kickstarting a mod as well, though that's a different topic.
If you want to ask for donations or put up a patreon that's perfectly fine, but if you don't have permission from the original developer then you can't sell your mod.
IDK, just my opinion, and it's, as always, subject to change.