People obviously haven't done much research on sky burial if they think it's so fucked up. Most, if not all the people in Tibet are Buddhist, and it's against religion to bury the body. Instead, you're expected to cremate, but fuel is already a scarce resource that you need for cooking etc. Either way, burial isn't an option and because a lot of these people live so high up in the mountains, the oxygen content and cold basically eliminates any decomposition even if you just left them out in the open. Ever read about the bodies on Mt. Everest? They last forever. So the best option is sky burial because it ensures you don't just have bodies laying around.
It's one thing to feel uncomfortable but you don't have the right to act like your culture is better just because you don't like something. Especially when you barely know anything about it.