I read an article yesterday, don't know if it's true or not, but it said Gen Kerr is not even a real general. The article I believe said he was a Lt Col when he left the national guard, he was never was in combat, he never even left the US. The title of general was bestowed upon him later and was simply an honorary title.

It is just a state title actually. And while he never reached the rank of general, it is still customary to address him as general.