What do blood elves eat?
They only eat real food purely for the experience and the flavor. It would explain how the old night elf empire managed to displace the Zandalari so quickly. Isn't conjure food based on DnD though?
Can a Blood elf be a druid?
Why Dwarves can't be Druids is more of a faction balance issue at this time (despite Alliance Pandaren being shaman) but the reason Blood Elves can't be Druids is because of race balance within the faction.
Do blood elves eat meat?
Yes, they do. At least canonically, they do. They regularly hunt for food, usually rabbits and game, like the Noldor or the Avari, or they fish, like the Teleri. It is just Peter Jackson wanted to make fun of their perceived “sissiness”, so they don´t eat meat, and only munch on salad in The Hobbit.