I have seen resumes with 20 different languages. I simply email them to rate on a scale of 1 to 10, how good are you with each language. (So that I can have interview questions on their better language). Surprisingly (to me) or maybe not surprisingly, a lot of such people never get back to me on their ratings at all. It could be the same "weird, insecure defensiveness" you are talking about.
I can't speak for those people, but I might be put off by a request for 1-10 language ratings, rather than asking what my core skills are, or something about choosing technologies for a given problem. 1-10 ratings strike me as a bit like, "what are your weaknesses?"
