Used to bug the shit out of me when I'd walk into base ops (sergeant) and they'd auto-sir me. Brief explanation that, no, despite the bag, I'm an E-5, you can call me Sgt, shithead, whatever, just knock off the sir. Still sir this and that sir. FFS.
Then I finished OTS, now immersed in my newfound Blue world, was when I finally noticed, they're all sir/ma'am-ing each other. MSgt calling A1C sir, SSgts calling each other ma'am. And also calling me sir. But since they also call the coffee pot sir, seems like much less of a courtesy extended. Its a culture of diluting the enlisted rank structure, delineation and responsibilities within enl/NCO ranks, and the enl/off relationship. A continuation of the mindset leading to a SrA stopping a Capt for ________ infraction, and if the Capt does not accept the correction on the spot, the SrA tells their Shirt, etc, etc.
My opinion, from the perspective of having been proud to be addressed as Sgt, because it meant something, and I knew early on that if I ever poked a finger in a Marine Captain's chest, I would pull back a bloody stump, regardless of what clownery he was wearing. But that's where I grew up, I guess.