but I thought spelunky was already a roguelike-
There's two definitions for rogue-like, and rogue-lite. First: like the game Rogue, or fairly different. Rogue-like is like Rogue. Second: with, or without meta-progression. Rogue-like is without.
It's like how Doom-like became FPS, but in the case of rogue-likes and rogue-lites, they didn't change the words, and so a conflation between the old, and new definitions came up.