Exactly. Many of us were taught to salute when wearing a uniform, but when out of uniform, to pay respect by standing and removing any head cover. This is not disrespect and nobody should get bent out shape.
The AF teaches this:
In military uniform, outdoors - salute, indoors - stand at attention.
Out of uniform, indoors or out - remove head cover, hand over heart.
There might be some different traditions, since I was briefed at an Army post that during retreat we were expected to stop the car, get out and render proper courtesies while on AF bases we stop and sit at attention in the vehicle. (If you’re in you stay in, if you’re out, stay out.) Maybe this is different as well.