Since when is it unacceptable to draw?

I never knew this was an issue but it does sound unreasonable. Perhaps it is because they’re aware of this as your hobby/other job and nobody wants you getting in hours for your other income bringing activity. Of course, this is assuming you get an income from your drawing.

Maybe your boss is jealous of your talent. Maybe he just wants to bust your balls. Maybe he wants you to quit. Who knows what lurks in the hears of bosses? The Shadow knows!

I have no answer to the why question, but here’s a thought: Is it the drawing or the content of the drawings? Do you draw well-muscled super hero type things with semi-naked ladies? Or terrifying scenes of mayhem? Or huge menacing dinosaurs? Do you add sound effects to your comic figures as you draw? And who complains? Have you discussed it with the person who complains?

Do they say that it is okay to do all the other things you listed, or is it the drawing more visible to others that you are doing your own thing?

Perhaps they think you’re good enough to get paid for drawing, and are therefore using company time to do something that you’re getting paid for doing?

I agree with @Simone_De_Beauvoir and think that the problem is likely that they know it is something you do on the side and don’t want to pay you for it. I think if it was a hobby and just truly a hobby there would be no problems.

I agree with the thought that it’s because drawing is something you get paid for, and they dont want you to do it on company time.

I don’t get paid for it, it’s a labor of love. In regard to whether or not I could quit, it’s the Navy, I’m under contract. The boss hasn’t even seen what I draw, just that I draw. I haven’t really talked to him about it. Should I confront him politely and just ask him why?

By all means talk to him. You’ll always wonder why if you don’t. And only he knows the answer.

Maybe he’s afraid that you are getting paid for it?