This is a fundamentally flawed argument.
First of all, if people are getting to where they want to go faster, easier, and happier, that is a good thing. If you want to argue that everyone needs to be a hermit who never leaves home and orders everything on Amazon then you will never get your way because people fundamentally want to travel to see the outdoors and nature around them, to see their family and friends, and just to adventure. Eliminating vehicle deaths by making travel impossible is not a noble goal.
Secondly, it's based on the idea that people even can drive more than they already do. Road congestion in most major cities is already the limiting factor that pushes people to bike, walk, or take transit. Even if AVs make it easier and cheaper to take car, you're still not going to do it during rush hour when you can bike.
Thirdly, it's based on the idea that AVs are only going to be slightly safer than human drivers. We have no reason to think that's the case. Humans are fucking terrible drivers, and it's highly likely that AVs will be several orders of magnitude safer than the average human driver.
Fourthly, it ignores other secondary effects to AVs, like suddenly not needing nearly as much parking, freeing up both parking lot real estate, but more importantly, freeing up on street parking, creating more room for actual traffic to move, and their increased patience not causing constant traffic jams because they tailgated someone and then slammed on the brakes.