Don't be angry.
Shit like this happens all the time. I used to complain until I found out drinking with the right company can actually be quite fun, the age matter is of extremely little concern. Being a teenager is all about experimenting with different types of behaviour, and discovering what works for you. I used to be like you, I moaned and got angry when this kind of stuff went on, and a lot of people really didn't like me for it.
My advice to you?
Suck it up, maybe even join in. You'll be socially accepted if you don't ostracize people for acting like kids. I'm not saying get totally uncontrollable, but a few beers never hurt anyone unless they were thrown at you. This isn't a lecture from a 30-something year old, these are kind words of advice from a 16 year old boy who has never smoked, had gratuitous sex, and only gets drunk on the rare occasion. Before I started acting my age, people found me boring, and frankly insufferable.
I don't know if that's what you want, but I certainly didn't enjoy being anally moral all the time, making myself feel better by saying "but I'm in the right". I'm much happier now, having tried it, and actually accepted by my entire year of peers.