If you don’t know what a scanlator is, it’s a portmanteau of scan + translator and is a person or group that scans and translates Manga from Japan.
Online theirs this unspoken rule that scanlators seem to follow of not scanlating if another group is scanlating the Manga.
But the problem is that sometimes you can get stuck with a bad scanlator either from not translating things well or being a horrible human being and inserting that into the translation or just ruining the Manga somehow or some sort of combination of those.
It’s why I’m fine with multiple scanlators especially when theirs a bad scanlator ruining things
It’s not officially written anywhere, but multiple scanlation groups have stated such a rule. It is usually a courtesy thing and looked down upon to scanlate a series someone else is working on since scanlation takes a lot of work, and as you said these people are volunteers so they are unpaid.
What OP is saying is a real problem though. Sometimes there are really poor translations and due to this courtesy other groups will avoid working on the same series.
I agree with the OP here. Courtesy is one thing, but if your scanlations were superior in the first place there wouldn’t need to be competing translators. As with all art, you want to put the best foot forward and do the art piece justice when presenting it. Many of these scanlations are straight up lazy, and others are downright damaging the original work.