My guess is that's it's more efficient to use the body to feed clean air to the propeller than to create lift.

Microsoft absolutely does not override the HOSTS file for their websites. Now Edge might be doing something, or maybe you didn't block everything fully but Microsoft only has a few hard coded HOSTS entries and it sure as hell doesn't include stupid stuff like the Bing website.

Not true. Windows ignores the HOSTS file for a few services like Update but the telemetry servers are not among them. You can find this confirmed by users if you search.

I think people are crazy to use Windows as laxly as they do and almost all my use of it is done via air-gapped PCs, but this has been a long running urban legend since Microsoft announced the use of hard coded IPs. All of the services they put that way were dangerously susceptible to hijack and it was actually one of the rare things they got right.