When an E-4 calls me "hey" or "hey man" knowing that I am an officer, should I bother to correct him?

Absolutely. If no place else in society the hierarchical structure must always be conformed to in a military environment. That means strict adherence and recognition of rank. Without it, structure breaks down along with military efficiency and the quality of leadership.

This is unacceptable behavior on both the enlisted and the officer, and needs to be corrected immediately. When I served, that kind of disrespect to an officer would get you extra duty at a minimum, and would not be tolerated. Yes Sir, No Sir, excuse me Sir, would be the correct answer.

Don’t allow a soldier to set standards, ran into my a doctor a CPT later MAJ when I was his medic at a bar. I called him sir and he kindly told me to leave it at work because he new I’d uphold the standards at all times however I’d still call him sir just because it was right. I highly respected the guy and he knew it and when I became an NCO I upheld the same standards, we aren’t equals that dude was literally a doctor!

I would probably nicely remind him I am always his superior officer regardless of whether or not in uniform. The real concern I would have is that it is hard for most people to always switch back and forth; consistency is better. I still call retired friends of higher rank sir or ma’am; help them develop good habits. I assume most senior enlisted would concur

You absolutely should and immediately at that.

Yes,
You should correct him, it shouldn't even be a question. We have to start back being leaders, and start enforcing what's right.

RU shitting me.... I had my issues with the officer corps. But, I never disrespected the insignia their wore on their collar. The mere fact that you were not in uniform just does not justify that way to address you. If he was in my section I would make sure that he was instructed on how to address an officer. I have interfaced with midshipmen, boot Ensigns, and Commander SEVENTH Fleet (Adirmal Thoms Moore).

That not just Offier or NCO 101 its soldiering. You should know that answer. Military is getting to soft or caring of hurting feelings.

You're a CPT, and you honestly don't know the answer to this question? Things have really changed in the military, I guess. Certain customs and courtesies end when you take off the uniform, others are part of the military way of life. The military is not a 9-5 job or a social club, your role doesn't stop when you put on civilian clothes. You carry an ID card that shows where you fit in the protocol when you are not wearing rank insignia, should the need arise. Every soldier is (or used to be) taught how to make on the spot corrections while in civilian clothes. A courteous greeting, introduction of self and presentation of ID, and a tactful explanation of why you initiated the conversation. Now, if soldiers are taught to do that, what does that suggest about military customs and courtesies concerning rank? It suggests that you are a CPT all the time. He is a SPC all the time, and if he knows you are a CPT then "Hey man." is not a proper way to get your attention. When I was an E-5, a PFC attempted to get my attention that way while we were in uniform. He got it. I would expect an officer and a gentleman would be more tactful but no less firm than I was in making the on the spot correction of military customs and courtesies.

At Ft Carson people who failed to address officers proper attended reveille and retreat saluting the flag for 30 days