The reason is that Microsoft as a company is all-in on "data-driven" everything. They're trying to get their customers to adopt this approach too (and mostly succeeding, our company execs are constantly going on about it). Disabling telemetry breaks this so they make it as difficult as possible. Because that's where they're planning to have their major value-add.

I really hate it too. But it seems so be so heavily anchored in their strategy that I don't expect them to lighten up about it.