I'm trying to understand but struggling -- so it is specifically the phrase "one of the only" that bothers you, but the example of "only five minutes late" is acceptable? And the issue is that "only" in that context doesn't mean a singular item, but rather a group of ambiguous size?

It doesn't really bother me, I just think it's not fit for purpose the exact same way as could care less to communicate not caring.

BTW thanks for the hot tip regarding the posting delay feature! Lord knows I need it, nothing induces https://en.wikipedia.org/wiki/L%27esprit_de_l%27escalier like hitting that reply button :"D