I've never heard this band before, but I'm guessing they're... what? An emo version of HIM?

Basically imagine Motley Crue without the attitude.

I think so!

The video was submitted in part because these people are very obviously in their 20s

Possibly even mid 20s in a few cases.

Dunno about that, sociologists went back to goth kids from the 90s and found them aging pretty okay:
http://www.guardian.co.uk/education/2011/oct/24/goth-culture-r esearch

From personal experience, if you haven't done anything too extreme with piercings or tattoos, goth blends pretty well if you have the common sense to have your tastes grow out of the fishnets and PVC for your day-to-day life. The wost crime of most corpgoths is being more dressy than everyone else at the office, not being not dressy enough.

I'm sure you can find the 30something still in their Marylin Manson t-shirt, New Rocks and eye makeup wondering why they can't get an office job, but "refusal to compromise between growing up and whatever leftover bits of childhood you refuse to leave behind" isn't exactly a trait exclusive to goths.

Well, yes, that's the sort of goths I've had experience with, that I can comment on, the guys and gals still rocking the heavy black eye makeup and the clove cigarettes and the posing and the hanging out at Denny's late at night in a surly cluster around a table, exchanging edgy jokes in public and hoping to freak the normals or daywalkers or whatever and all that well past...well it was never a good thing for them but they've carried it on too long. Sorry folks, you're not special, you're just another clown stuck in extended adolescence who dresses like a goof, not exclusive to goths these days.

Corpgoths, not something I've had experience with, so I admit I wouldn't know. Unless there was one right next to me at some point, and I didn't know...dun dun dunnnnnnnn.