Pedestrians should not be on the road.

No, cars should not be on the road.

Roads were built for cars.

That's not actually the case in many places in the US, they were forcibly taken for cars in the same way electric streetcar systems were taken from us:

> Before the American city could be physically reconstructed to accommodate automobiles, its streets had to be socially reconstructed as places where cars belong [..] Until then, streets were regarded as public spaces, where practices that endangered or obstructed others (including pedestrians) were disreputable. Motorists’ claim to street space was therefore fragile, subject to restrictions that threatened to negate the advantages of car ownership.

https://mitpress.mit.edu/9780262516129/fighting-traffic/

Coming up with a fact that roads existed in the ancient times is not a gotcha. Most of the roads today did not exist back then. 99% of the roads I have driven on did not exist before cars.

Crosswalks

Crossing the road is different from what is being discussed which is riding along side cars.