Ravana was a vegetarian? This is news to me!

Do you have any textual source to backup your claim? I doubt it.

Both Valmiki Ramayana and Vyasa Mahabharata refer to Ravana as पुरुषादकः = eater of Humans.

For example:
https://twitter.com/TIinExile/status/1181648600062779392?s=19 https://twitter.com/KumariRadharani/status/1246833742615896065

Ravana warns Sita;

"Oh Sita, if you do not accept me as your husband within 2 months, I will K!ll you and eat you for my breakfast". (Valmiki Ramayana 5.22)

I am SHOCKED to see people claim that Ravana was a Vegetarian!