I think you misread their response. It’d be similar to ask “How long does a timeout last” - it depends on the time affixed to the state - timeouts have no inherently defined length.

I think ban in the tech world was originally understood to be permanent - but in the real world ban has always had the flexibility to have an assigned term. As the internet has grown it seems that ban is gradually returning to being non-permanent though a lot of systems will still differentiate between a ban (permanent) and a suspension (temporary) - though, again, there are instances I’ve seen of “Account permanently Suspended.”