Why does that piss you off? It sounds like you had a conversation. Maybe he did get it, just thought you were wrong and/or overweighting things you found important, that he did not.
If you want to hamstring your career by not having a presence on the world's biggest careers website then that's perfectly okay - but I do not think a professor at University should be advising that course and would be failing their students if they did.
I am not saying you're wrong, and I do understand the reasons you might choose this path - but that doesn't mean you're right and that your choices are good advice for everyone.
Again, why? Both of those "attitudes" are reasonable.
We do live in the times of privacy exchanged for service. At least this service directly impacts my ability to earn money off that exchange.
LInkedIn is also objectively better at everything you use LinkedIn for: with the exception of, you guessed it, privacy. The only real option you have here is to not use it (and accept you are putting yourself at a disadvantage)
I get the desire to retain privacy, and to not use a product that goes against your code. I just think your reaction to a perfectly reasonable, and entirely predictable response is perhaps naive? Or just unwarranted. You priority privacy over maximising salary potential - an entirely reasonable thing, but not one most people would do.