I think re-explaining things that happened in previous seasons is a different issue. They're worried that you don't remember what happened because it has been so long.
And that's fair. I know I watched Season 2 (and it definitely had my full attention, because I'm incapable of doing two things at once), but the only thing I can actually remember about it is the episode where El went to Chicago and met some shadowrunners. And something about tunnels. Everything else is a blur.