In all honesty, I think many virgins [not all] bring it upon themselves.
Example one: I don't like to have a conversation with a friend and have them say "I did _____ with my ______ last night!". This isn't generally something I'd like to imagine or picture in my mind. Just like I wouldn't want to hear that, I also don't need to hear that you've never had sex. I honestly do not care, and it's not something I need to know.
As such, if you decide to be tacky and make your sex life [or lack thereof] everyone else's business, don't be surprised if I see you on par with Paris Hilton in terms of trashiness.
I personally have no virginity-dar, so I can't tell who's a virgin and who isn't. I wouldn't make fun of someone [or more likely, call them trashy/tacky behind their back] who was a virgin and didn't broadcast it, but I think the Jonas Bros. and their Purity Rings thing is inappropriate and just as trashy as "leaked" photos and sex tapes. There's no need to make a vow public unless you're telling a potential partner. If you wouldn't announce your preferred sex position with your current flame, you shouldn't announce that you haven't had sex either [and how that includes oral, anal, whatever.]