Ooh - this is something that irks a lot of people. Whether or not it's intended to be nice or to be belittling, I pretty much find it ignorant and rude - and bad, bad, bad. So do most of the other people I know (including women, men, or young people). Just yesterday I overheard a young guy complaining about a woman who called him "hon". When women us "dear" and "hon" it's just as aggravating, even if they're mean to be nice (which a lot of times they're not).
A car salesmen (very nice, not intending to be offensive, and a lot of younger than I ) once called me - get this - "Sweet Pea". It REALLY wasn't very flattering because it was pretty obvious I wasn't three years old, which only means someone isn't seeing you as an equal adult. (I don't call the guy at my bank "Sweet Pea", do I? )
I don't mind "dear" from someone I know well and someone who's a lot older than I am, when it's clear they're using a genuine "term of endearment". Other than that, everyone needs to keep their "dear's" and their "Sweet Pea's" to themselves.