Do you know what an interpretation means?
That means that there is an actually wording on a specific situation that is outside of the rulebook. Usually the casebook gives interpretations. That means that the NF clearly has addressed a situation where we can give a T in the locker room. And I do not read a specific rule that says coaches can be given Technical Fouls for comments in the locker room.
You are assuming that the NF (or any organization) wants us to give Ts for what people do in their locker room outside of a very specific situation dealing with electronic equipment. And all the examples of official's jurisdiction, involve things that take place on the court and in your presence. If you are in a room next to another room, that is not something that takes place in your presence.
I compare this circumstance to the rule that was put in about pulling out your jersey (in frustration). That was not ever considered a T other than personal tolerance or interpretation. You are taking an obscure rule to apply to a very specific situation that has never been addressed by the NF you have shown me. Now the rules give you the right to make some judgments that are not stated in the rulebook, but that is a stretch to take a situation like this and start giving Ts. But in my state any action that is considered out of bounds or unsportsmanlike outside the court, can be handled with a "write up." And this is why I said what I would do. I never told you what you should or should not do.
Peace