Why would anyone be so bothered by a usage that is different against one's own
that it would set one's teeth on edge, cause one to shudder or any of various other
reactions I've seen described on this and other language forums?

your right; its a mute point, but I really do get flustrated and want to go screaming into the night when folks mitigate against correct usage, irregardless. I can't reiterate this enough, ect.