I saw a little bit of an episode this season. I can see the series is not for me anymore. The Master switching to a good guy/gal? It is ok that he/she murdered people because people eat meat??? Sorry no thanks.
It’s possible that seeing a scene out of context isn’t sufficient to understand the series. It’s not clear what is going on with Missy just yet, but you are certainly not supposed to be trusting her with open arms. This Doctor certainly is darker and rougher around the edges, and doesn’t always harp on his appreciation for the importance of each life, etc, as the last few Doctors did.
The show goes through phases, and the Doctor varies in personality. December 26th, a new guy will be in charge and a new actor will play the lead. Maybe it’ll be more to your tastes, or maybe not.