adlid
The resolution of that thread appeared to be that ‘turnstile’ is the best we have at present for mapping TFL gates and is the current consensus elsewhere. Indeed, that tag is used across the rest of London for the same purpose, where stations have gates marked. Also, turnstile seems like an appropriate enough name from common usage of the word, even if it doesn’t match the exact dictionary definition.

So unless someone goes through a new tag proposal, there’s not a lot that’s actionable here.