I tend to give the pilot and FAs the benefit of the doubt but I do find that this happens quite often on those ~1:30ish length flights out of ATL. Specifically with ATL based flight crews. I fly FLL-ATL and back routinely and I would say 1 in 10 you'll catch a crew with just zero interest in doing anything and hiding out in their seats under guise of safety from turbulence that never happens.

It is always ATL based flight crews and if you fly the route enough, you start to recognize the same FAs. It is a short enough flight that I typically won't beat down Delta's door to complain but it can be frustrating to be in C+ and essentially get zero service.

Again though, I give airlines the benefit of the doubt here because I definitely would not want to be on the flip side where you have passengers and crew doing headers off the overhead because the seat belt sign was off and actual turbulence happened. That's an area of aviation where I'm firmly in the better safe than sorry camp.