While I don't know how they in particular acted, I can assume there was nothing awful done while they were drunk?
If not, you shouldn't be getting so angry over that. There's nothing wrong with getting a bit drunk, even "Under Age" (LE GASP!).
Hell, they even had the decency to stay indoors and have a house party with it.
I don't know if you've been unfortunate enough to grow up in a gated or highly religious family, but your reaction seems WAY overblown.
Go have a walk around Glasgow at night. Then tell me how awful your friends have acted.
Though, saying that, I just had a scroll through the thread and someone pointed out the OP is about 20 something...
So I'm suspecting this whole thread is a pointless troll. Or just really creepy...