Is this common amongst languages no one uses or languages that are past their prime?
I don't know about the case in question here, but some programming language communities have had to deal with hate, flames, mockery, and the associated trauma, for decades now.
And a programming language community is not exactly chartered as a trauma-metabolizing, cathartic organization, to say the least.
This means you can get unwarranted, instinctual, direct pushback and possibly rude treatment from community members where you might have the opposite in other, growing communities for example.
There are also other lenses that apply here, but that's a big one...
It also seems that mapping this kind of outcome onto prime/past-prime doesn't uniformily cover the outcomes either.
However there are some interesting workarounds that I've seen, depending on the situation.
Anyway, just to say I've noticed this kind of behavior too.
(My guess from your title was that you were asking about the language itself being unreasonable and rude. Having programmed in System 360 assembly language, and several of the x86 assembly languages...I'd say YES.)
There are certain programming languages which are technically promising but many people have problems with the creator, I know that.