Haha, yes, what counts as a long read definitely varies by person! I'd say 20,000 is a fair benchmark. I am happy to read 100k works but those are relatively few, and to me a short read is anything under 5k.

I agree that within a rec post on, say, some other theme or for a single fandom, I can easily scan for the word count and I wouldn't consider organizing by that important unless it was a very long list.