Since when? I work at a games studio, you couldn't imagine more dorky people than those who work here, and yet there's several serious petrolheads here, we go to car meets, one dude rents a barn to keep all of his rare US-imports and to work on them in his spare time.....

I don't understand(and rather dislike) the notion that if you are a nerd/into computers, you have to automatically dislike cars.

Depends on which problem space around cars we're talking about. Are we talking about the vehicles themselves? Then those aren't referred to by nerds in colloquial usage.

That being said, there are a lot of nerds who obsess about things like highway systems, road planning and the like. There's also the electric car space, the AV space, etc.

Wrong, anybody who obsesses about anything is a nerd by definition.

Obsession about muscle buildup strategies at the gym has rarely been associated with rhe term “nerd“. Those people can be quite nerdy, and even connect well with regular nerds if they find common ground, but isn't the mainstream accepted term “jocks“?