[2021] farming illegal?

Farming is a grey area and we do not condone it, but it is not outright bannable. It becomes bannable when someone is being forced to farm as this turns into griefing, e.g. XYZ doesn't want to farm, but the killer and the other survivors refuse to do any gens, so XYZ is forced to do gens alone or griefing such as working with the killer to kill them, etc. etc.

https://forum.deadbydaylight.com/en/kb/articles/139-game-rules Here is more about griefing.