First of, I think that many people posted helpful advice posted. There are a lot of 2cents that you can gather from that, you might even make a dollar
In my dojo I had a similar situation in that I had almost lost trust in Sensei and really had to dig deep to validate me still going there to study. Although Sensei never degrades thestudents I and other some other students found that we were getting more annoyed and annoyed at Sensei's style of teaching. We al wanted to stay because we knew Sensei knows much, can still teach us a lot and because training with each other is great fun, but we felt that mat time wasn't used effectively eg. Sensei talked a lot! I discussed this with my closest friends from the dojo and we also discussed this with Sensei's assistants adding to that the question that the assistants please discuss this with Sensei. In the end we were tolled that Sensei had his bad periods and this was one of them. Today the atmosphere in the dojo on all levels is good again and I believe that everybody has re-enrolled for the next season.
Long story short: my 2 cents is that you talk to the assistant(s) regarding your troubles. It feels good to be heard, they might know something you don't or maybe they totally agree with you and although you cannot change Sensei's personality, you can hope change Sensei's behaviour, albeit in small incremental steps
Oh, and regarding the degrading remarks, I think that that's a big no-no in the dojo. There are times when tenkan works best, but I think that irimi is at its place in this situation, but remember that irimi can also be gentle