The customer has no right to deside on issues that affect _others_. A customer can decide on what affects the customer. If car A is more dangerous for other people than car B, then it's for somebody else than the car customer to decide what should be allowed. A car owner can't decide that "it's fine to drive this car which will kill other people because of its design".

So if I want to, I should be able to drive a literal tank? What a poorly thought out argument.

Cars are a danger to others, that's why your own choices shouldn't be the only thing that matters.

Yes, like in the US - you can get a permit to drive one around.

On public roads?

Obviously.