I think the reason it gets so much hate is because its everywhere. It's a bit like minions; they were actually pretty cool and stuff at the start but then they started appearing on everything like bags, clothes, in ads and know everyone's just sick of them, so they hate on them. Frozen was good but now its just annoying because its everywhere.
Truly a masterpiece
I plan to see Zootopia and I think I'm going to like it more than Frozen