I think people have the right to be offended. It doesn't really offend me, but the behavior is beyond ridiculous. Not the type of behavior/person I would want to surround myself with, but definitely not someone I'd wish death upon. There's people that literally hate our country, or there's someone who hates the color of someone's skin, etc. and I still wouldn't wish death upon them. So wishing death upon someone for defiling a symbolic piece of cloth (yes it is a symbol, but it's just that...it isn't your grandma). Heck, I wouldn't even wish death on someone for urinating on my grandma even though that person could use some prison time and maybe even a good beating.
Someone can clean that flag out and someone and curse the woman out, too. But you don't come back from death.