> That's only for the telemetry that happens during the install process (if I've read the link correctly).
Wrong. That's for the dotnet cli tool to phone home each and every time you run a command.
https://learn.microsoft.com/en-us/dotnet/core/tools/telemetr...
Microsoft even provides a page which showcases summaries of some of the metrics they collect from you if you don't disable this feature. These metrics even include MAC addresses.
https://dotnet.microsoft.com/en-us/platform/telemetry
> Seems quite reasonable as long as we accept them sending telemetry during install.
There is nothing reasonable about this. You should not be required to have tribal knowledge on how to use arcane tricks prior to running an application just to avoid being spied upon. It's a dark pattern, and one that conveys a motivation to spy upon unsuspecting users whether they approve it or not.