The thing is a lot of them do but rely too heavily on mtl. People who's English is there second language tend to be better imo
the translators with bad english usually know perfect english and is using machine translators (mtl) like google translate. they're very lazy and don't bother with fixing the grammar
Lazy seems about right, especially when you find the name of the same character changing 3 times in the same chapter. I don't think that's an MTL/grammer issue there, because copy and paste is a thing in all languages.
I wish all the people who plan to translate a novel, manhwa etc would at first learn to speak English.