"might the cluster of behaviors deemed "flirting" be considered simple decency?"

I've often thought this myself. Also read an article about a study (which I'll have to look up again) that found that many people didn't know when someone was trying to flirt with them in a bar/party setting, and that many people picked up on flirting when it wasn't actually there.

And yes, this is a huge [citation needed] until I can find the post I'm thinking of :)