Um, sorry, but I've seen it many times over.
Search the DIS for 'tour groups' or 'cheerleaders' on the DIS! You'll find LOTS of folks posting similar experiences. I'd never single out any particular cultural group (which happens on the DIS), but cheerleader groups and tour groups (of all kinds) are notoriously rude! Even outside WDW.
They think since most of the folks in the boat, at the pool, etc. are in their group they are at liberty to take photos on dark rides, chant/cheer, cut in line, etc. (They have easily self identified in matching shirts.)
Honestly, I don't mind a little group enthusiasm, but flash photos on dark rides drives me nuts. So yeah, I look to see who was ruined my ride expereince, and all too often they are wearing a group outfit.
Oh, and then there were the two flights I had to take where half the plane was part of an athletic team. (on the way to WDW) Even before they boarded, everyone else on the plane was aware they werea group. It was impossible to NOT hear them unless one was completely deaf. They were also wearing their colors.