Not USA, but I am somewhat patriotic. For those who actually don't understanding why burning a flag irks some folk: Flag is a symbol of a country. People who feel pride for their country, who feel like they really are a part of that country and root for it, are feeling something akin to being spat on when the flag is burned, as it shows disrespect for country and what it stands for, them included.

I don't judge people without context tho, as often burning the flag is a method of showing major dissatisfaction with how country is being run - in a sense, showing that one doesn't feel this connection anymore.

And when done "for fun"...well, idiots are everywhere, whatever.