The ethical choice is obvious.

The distinction is between "What I do with my computer is none of your business unless I choose to make it your business" versus "What I do with my computer is your business unless I choose to not make it your business".

It's insane that we are still having to justify privacy as a default, or that people continue to rationalize away the concerns.

Yeah, maybe if it's opt-in they won't have much telemetry data. Perhaps, in fact, it would not be much better than having no data at all. That will make some things harder. Major bummer. If it was easy to do the right thing, more companies would do it.