Why are some guys assholes?

I'm on a school trip, and there are three different 'groups' of boys (by groups I mean social circles). Mine is definitely the least 'cool' for whatever reason, and only two of my friends are on the trip compared with the other groups of five or six. On this trip we are staying at a location with a pool table. After we ate dinner, I went to play 8 ball solo, as my friends didn't want to play. Right after I begin to set up, three from the 'cooler' group of guys came to the pool table. I was like "you want to play?" and they replied, "You know how to play sniggle?" I had a general idea of how to play, but since I'm not sure on their rules I replied, "No, how do play?" At this point they decided on the order (I was not playing - they could have easily added me in (I'll try to find a video of the game, it's meant for many players) and started playing, leaving me unable to play on the POOL TABLE I ARRIVED TO FIRST.

I know I'm sort of the weird kid (I lowkey don't know why), but they really didn't have to take the pool table, which I was happy to play on alone.

Next time should I not let them have the table, or would they think even less of me?