Why do all restaurants in spain cook with lard?

Have you actually visited the kitchen of each and every Spanish restaurant or cafe to ascertain for yourself the actual cooking fat used ? Since this forum is for cameras, I presume you have some photographs of this expedition which you can share with us ? We are agog.

They use lots of pork and lard is cheap??

Because they prefer natural ingredients instead of the partially hydrogenated corn oil Americans use. Besides, for food anything in moderation is ok.