Would the 30min discussion during cargo loading count against the sterile cockpit rule? Obviously the ground is less than 10,000 ft but surely there's a point in time that defines the "start" of the flight when the rule goes into effect.
Most of the pre-flight work on a plane on the ground is safety critical, with rules around them written in the blood of somebody who wasn't paying enough attention and missed them.
Paying attention to things like weight checks, fuel checks, and systems bringup should take priority over gossip.
Imagine if your prod system was on fire, and while waiting for a diagnostic query to run, you talk your coworkers ear off about how you really dislike working with another coworker. It's just not the time to do that. Every single flight requires your attention, and letting things become routine is called "normalization of deviance" and is step one to an event that kills people.
