I won't talk about Cesar, but I have raised 3 french bulldogs and one boxer from they were puppies, then we got our basenji. Before Yuna came into our lives, we read a lot about the breed. I read that kindness, praise and rewards is the best way to raise them, and I have to agree. I can only talk about the individual we got and not all basenjis in general, but I had to take a few steps back and reconsider methods when training Yuna.
I have always been a fan of positive reinforcement, praise, and basically teaching dogs in much the way we teach our kids. Punishment in our house consists of the fun ending. Like a puppy biting means that I will remove myself, turn my back, and ignore it until it stops. So the puppy learns that biting = no more fun. This sort of training takes time, but the point is that it's learning. Some learn quickly, some take more time. We have to expect this, since individual dog mature at a different rate.
With Yuna, I realized that any "rough" behavior from my side brought out the fight in her. Like if she stood with her front legs on the table, she was okay if I pushed her down gently or blocked her access with my body, but if i pushed with even a hint of force, she would start biting (as a puppy, that is). Not hard, but she was protesting my behavior. My experience with dogs made me realize that I had to take a step back and train this particular dog with even more kindness and patience than I normally did.
To be honest, I have no problems seeing why the basenji as a breed is known to have aggression issues. A very proud, strong-willed dog with a lot of courage won't be pushed around without fighting back. Violence breeds violence, and sadly there is a lot of dog training that consists of showing the dog that we are their physical superiors by using force, instead of teaching them and guiding them based on well know learning principles.