It's just their culture I guess.
And yes they don't mingle, and a lot of them laugh at everything when it's not even funny, and they're mostly like ^____^
BUT I wouldn't generalise and stereotype though.
However...judging from experience...
In primary school, I was in the gifted & talented classes for four years, so I was the only Arab among all the Asians, and they used to treat me like shit!
They always marginalised me, left me out, and looked down on me and thought I wasn't as smart as them because I wasn't Asian. There were a few nice ones, but I knew a lot of them laughed at me behind my back. I hated class because of them, but I just kept to myself. The lonely Arab in the dark corner.
And they were always like 'cooties, cooties!' and giggle with each other and talk about pokemon, and I would be like 'what the hell...I WANNA GO HOME!' in my head.
Anyway, I'd escape them at lunch and recess and hang out with my Arab peeps, and we'd eat our pita bread sandwiches together.
Idk. I would never generalise though. It was unfortunate that I was in a class for many years full of really rude ones, and I still come across lots of snobby ones, but I've met some cool/alright ones too...they keep to their own, and so be it. I'm not going to get involved with people who aren't going to be open.
A lot of us connected on facebook last year, and I looked at their pages and was like HA, my life is better than yours lol.