Some people did indeed abuse that knowledge, but it was rare.
A few people were, by request, "ex-directory" and not listed, but again, that was rare.
Most people were not only absolutely fine with their phone number being public info, it was more useful then than a publicly-known email address is now.
Boy, what a complicated and serious question. We should form a committee to discuss exactly where our community places reasonable boundaries and adjudicate blurry edge cases. Who could have predicted that a policy like "if it's legal, it's allowed" would lead to problems? Surely no one with a few dozen billion dollars to set on fire would be that unbelievably stupid.
comment may contain hyperbole, do not consume for statistical purposes
Consider the following: The Twitter files contains a lot of private information and outs employees whom have received direct harassment.
The ElonJet account contains publicly available information on a very accessible site. This does not make a statement about Musk nor does it tell who is inside the jet at the time.
Which is closer to doxxing?
When he's not the object of the speech in question, he seems to think that things like calling people pedophiles is free speech, so he generally seems to be a free speech maximalist and I'm guessing the answer might be yes.
I don't consider a lot of things to be free speech that musk apparently does, but there's a big difference between him being a free speech maximalist in general and just supporting free speech when it's convenient.