I mean, it isn't really hypocrisy. They're two different stories that he had different ideas on how to proceed on.
In Aliens, he has set up a dynamic the he would have liked to have seen move forward. I personally love the choice Alien 3 made to strip Ripley of all of that, but I understand him being bitter of it.
With Terminator, Cameron was returning to a franchise that he pretty definitively ended with T2, and yet had been poorly followed up on over and over again. In order to do something interesting with the material (and with Sarah's character – and the new T-800, too), and to separate this film from all of the sequels that followed T2, I think his choice there was the right one. It was thematically relevant to the series as a whole, and kept the action going in a way that actually feels like an evolution of the story from the first two films rather than just a retread of it. John still had a purpose the he fulfilled, and continued to inspire a new generation. Sarah was probably more interesting than she's ever been. The T-800 was the most nuanced approach to artificial intelligence the series has ever had and an interesting thematic evolution of T2's ideas.
I don't know. I just really liked Dark Fate. Way more than I ever expected to. The worst thing about it is that it is so clearly setting up a sequel that will not be happening.