People loves to get high from time to time to have some fun. Yea, many of those people at those 4th of July parties have alcohol problems but its not my place to judge them for there acting. The only person I can control is myself.
Before I had a drinking problem, I would have fun being buzz. It would get me loosen up and feel free. Now I would get drunk or stay drunk for days if I start. I try not think about it too much because I will tell myself it's okay if you have a few.
Also think you are focusing too much on only the people who are drinking alcohol. You will see a lot of other people who don't drink at those parties too.