Out of curiosity, where do "I'm a humanist" and "I'm a transhumanist" scale?

But yes, outright claiming membership gratuitously for pretty much any wide group without further descriptors or evidence that this affiliation is somehow relevant to the discussion is usually not something to look favorably upon.

I wouldn't quite say it in itself lowers my opinion score of someone, but it might give me some light evidence towards adopting a lower-opinion-estimate model of that someone, which effectively would reduce the "expected opinion for that expected mental model".