one usage will feel like fingernails on the blackboard when a similar term may not

Exactly. Incent bad, descent ?? incense ??

When I hear someone say that some word offends esthetically and that word is only marginally different to many other words that do not offend I wonder what the real issue is.

And if my question did have that sort of rhetorical bait quality to it, that doesn't mean I'm not interested in folk's opinions in the matter. I think you may be on to something with this "sense of identity and community" thing . On the Great Vowel Shift, were there no prescrips at the time who recorded their dismay at the way them young rapscallions were destroying the language we love?

Then, if you don't like incent there's always incentivize.