I don't see what the issue is with the AI. Teah it can be a bit aggressive and sometimes a couple make mistakes too easily. The rubbing and slams though are part of certain forms of motorsport. BTCC, Nascar etc etc. In those taking and giving hits are part of it. Only things like F1 where the racing is much cleaner.
Also those people who are using the manual, watch it as some of the cars like the real life counterparts are actually faster when using automatic. So worth testing them in auto and manual to see what is better. Basically cars which are typically auto in real life are worth trying in automatic. You will find a few have higher top speeds and quicker acceleration in automatic, annoyingly.