"Code ghetto" is actually a term I've heard bandied about before, usually used to denigrate an ecosystem someone doesn't like, but in this case I think it's wholly appropriate terminology[0], and I don't think the offense taken at it is justified.

[0] This comes up top of Google for me: https://www.laurencegellert.com/2012/12/software-ghettos-a-f... and I feel that it conveys the meaning, even if you disagree with the particular ecosystems being denigrated.