Well that's just a silly comparison to make. No one is watching you in your home, you can stand or sit if you please, but if you're in a public setting where everyone is asked to stand for the anthem, you just do it. I mean if you see a family singing happy birthday on TV, you don't join in the song, yet if you're friend is getting his cake right in front of you, you're gonna sing along, sure you can simply not sing, but that's a good way too look like a jerk to your friend or family. (lol just the thought of someone not singing happy birthday as some sort of protest made me laugh)