Did any of you torque wrench owners post a thread asking if it was OK to work on your own gear? (I know the answer to that question already, but maybe you should think about it. The first answer in this thread was probably the best: If you have to ask about working on gear, the answer is: "No, you should not work on your own gear.")
And, yeah, generalizations are always stupid. (!).
I do wonder how people who work on their own gear know that they are doing it well though. Anecdotal evidence is not evidence, it's just gossip. If you work on your own gear, then what do you have to compare it with? Even if you alternate between doing your own overhauls annually one year, and having a shop do them the next, in order to compare them, you still have to wait twenty years to have ten instances to compare. And that's not enough to know.
The scuba industry is run by liability and liability insurance. If the stories that seem to get trotted out about gear failure, every time this discussion comes up, from stuff worked on by dive shops were true generally, then we would have had some legal rehabilitation underway by now. It is why things like recalls get issued. Liability, liability insurance, and liability exposure.