I'm always nice to recruiters if they make the bare minimum effort. If the job isn't a fit, I offer to stay in touch. It has led to great opportunities for me simply by taking advantage of the network effects offered by a recruiter link. Things turn up if you talk around enough.
I try to be nice to recruiters who demonstrate that they've actually spent 60+ seconds considering if my resume was a match for the position. (Including my stated location requirements.)
Occasionally I'll tell them that I'm not working on a different level of the software stack than their position requires, and try to point them in the right direction. No idea if that's helpful to them, but it's nice to feel like I've been kind to a stranger.
