Plus, who's going to respond? A Starship is the top of the line, best ship in the Federation, is a freighter going to rescue them?
As far as anything else with this episode, it's problematic. I do not pretend it's good. Sorry if you like this one, I don't and it's on my 10 I don't think about too much
Constellation had it's disaster beacon on, not necessarily a distress signal but it could be considered one.
The Intrepid didn't send a distress signal, but Starbase 6 lost contact and asked Enterprise to check it out.
Starfleet lost contact with Defiant and sent Enterprise to check it out.
(I'm starting to buy that theory they didn't like Kirk and gave him all of the bad jobs, like Dirty Harry.)