Disco opinions seem to always generate arguments, so I could understand if that was reasoning behind the deletion, but that follow-up indicates that it wasn't it at all. The best group I've found for discussion has (surprisingly) been Star Trek Shitposting on FB. There's a lot of goofing on the shows, but the mods are very against purposefully biogted / inflammatory content. But it can be hard to get a real discussion going because there are like 85K people in there and its easy to get buried.
As for season 3, I found the overall premise to be the strongest one so far, but the execution was maybe the weakest overall, just because they were (for once) not really pushing the envelope. I liked it overall - it started really strong and kind of petered out by the end, but think S2 was better (Pike was incredible).