xkcd

And what, are you going to restrict cars off the side street to turning right and then making a u-turn?

Yes. If there is not enough traffic for a better treatment, and the intersection cannot be made safer intersection, then left turns should be prohibited.

This is just a common as dirt configuration, especially in rural areas. I don’t find it remarkable at all.

Multilane thru traffic with turn lanes is not a typical rural configuration, at all.