What's the deal with people booing during the National Anthem?

[underpants]

Are they booing AMERICA?!?
Are they booing the flag?!?

Doesn't seem very patriotic to me.


----

Okay I was being sarcastic but it's a take on this whole thing I hadn't heard or considered.
Full credit gives to Colin Cowherd (sports talk radio) who alluded to this as part of his 2 minute commentary on it. It was just one line but I thought it was interesting.

[genxlib]

1. Everyone knows

The proper way to show respect is to hold your beer aloft and whoop drunkenly for the last three lines of the song.

At least that is what I have observed as standard behavior.