Fist off, no, you cannot be clingy and NOT be insecure. They are two sides of the same coin.
Second, in guys, clingy bleeds over VERY easily into creepy. If you've just met the guy and he's ALREADY following you around like a puppy and/or gushing praise and/or trying to make plans for the next two weeks, that just makes you want to scream "back off! and leave me alone! you don't even know me!" Remember that we girls have to deal with slightly different shit than you guys do. We're very sensitive to the whole clingy/creepy/jealous/stalker continuum, because the stakes are rather higher for us. If a guy trips our signals on that wavelength, we run. But with clingy, usually best-case scenario is that the dude is insecure, and that's not attractive either.
Mind you, I can be clingy. And that's one of my worst qualities relationship-wise. And yes, my clingy comes from insecure. Think Dora. But I try to keep it in check.
Anyway, with my own damages, I wouldn't mind a guy to be codependent with--but this is only after we've actually gotten to know each other and established a deeper emotional connection. And I would like someone who'd be emotionally open and commit to me and all that--but the thing is, someone who clings to you right off the bat usually isn't even into YOU, but whatever idea of you he's constructed in his head, and that's all sorts of deeply uncomfortable. Someone who seems aloof at first meeting gives off the signal of "I'm not gonna smother you or hold you up to some imaginary standard of perfection and then be disappointed that you aren't my imaginary version of you down the line," and so can actually be more appealing. Or at least more safe.