Oh yeah the jailbait ones are horrible but they're all from 2009 (everyone I saw was, at least) so around the time he started at Ars. Going on an hypothetical, even if questioned about it he might just have responded "I had a rough patch in my sentimental life and acted dumb, I didn't mean literal jailbait yadda yadda" or somesuch and maybe that would have been enough (not saying it's a valid excuse or anything but heh).
Notions of vetting gets thrown a lot these days with social media and whatnot but except when it is necessary (and perhaps there's a debate that journalists are public figures now) nobody got the time for that*. The US might be more lax on that but it's also sometimes a fine line between vetting and discrimination...
* Beyond the most shallow Google search.