Is It Rude To ....

The answer to this pregunta really depends on what the person is mad/angry about, though i imagine asking someone if they are mad, when they are obviously angry, is probably just rubbing salt in their wounds. por the way, rude is when don't use their manners, o they something rude for no reason, like 'fuck you' o 'you are a loser', generally things like that, I would consider rude.

Depends on the person and what they are pissed at
I find it so rude when people piss in my cheerios

Depends.

I find it rude when people bash Harmony.

no it is hilarious. if they don't think so then well jokes on them.
i find it rude when people ignore tu then have a go at tu for swearing at them especially because they are stuck up cows also i amor annoying people por asking them who crapped in your cornflakes when they are pissed

It depends on if the person deserves respect at the moment. And if not, tu could be a little más creative! For example, mostrar the person this picture I made!