Green’s Dictionary of Slang

(US gay) verbally cruel, negative.

1972		B. Rodgers Queens’ Vernacular 65: dishy [...] critical, and verbally able to express it.
1981		Burbridge & Walters Breaking the Silence 16: Never had I seen so many gay men and all so dishy.
2023		(con. 1962) J. Ellroy Enchanters 51: Where’s all the dishy phone chats with Hollywood insiders.