I kinda agree with you - I am not bothered by it -- just found it odd and possibly just not the right place. At least at my older daughter's game - it was just them having a little and no one was obvious or drunk or anything.
I have heard of one instance --- it was an away tournament where you stay over, that the parents got so out of control, the hotel asked them not to come back the following year.
Some of these bigger venues have restaurants/pubs that serve alcohol. I never really thought one way or the other, other than thinking a fitness type place seems an odd place to have beer and wine.
Until recently a parent told me the newest facility which is in my town was going to open a sports bar over looking the basketball courts. This parent thought it was a good idea (now granted he seems like he enjoys a few). I kind of shrugged - then this other dad mentioned I don't know if it is a good idea, some parents get out of control without any alcohol imagine adding alcohol to mixture...although most parents are actually pretty good, I've seen some and I'd have to agree there are some you wouldn't want to see with alcohol flowing through their veins.