It's not even about privacy, it's the basic ethical principle that you should ask for consent before doing something to me. It is a command line tool that I run on my machine, why should it be allowed to what I didn't ask it to in the first place?

Developers might think telemetry a good thing - then decent ones would care to convince the user that it's a good thing too. Some users will agree, some will not, but asking is just a basic act of respect and decency.