I don't believe anyone has a problem with the "act" itself from a moral standpoint. I think what people are taking issue with is the idea (or suspicion) that incidents similar to these will cause increased policing of tailgating and other pre-game activities. As an example of possible ramifications, someone who has had a few too many drinks, but is completely harmless and peaceful, may be more apt to get a public intoxication ticket in the parking lot or on their way into the stadium.
Wasn't there an increase (or at least the threat of) in public intoxication tickets after that man drown in the creek after the Cowboys MNF game years back?