This sounds like the type of stuff a company would require on their business laptops, so this might actually be a good thing for Linux adoption. Of course it sucks for people who were already using Linux for work and now gotta put up with this shit lol.
Defender on Linux desktops requires the standalone Microsoft Defender for Endpoint Plan 2 or Microsoft 365 E5 and E7.
from here https://techcommunity.microsoft.com/blog/microsoftdefenderatpblog/secure-linux-desktops-with-microsoft-defender/4560822
This sounds like the type of stuff a company would require on their business laptops, so this might actually be a good thing for Linux adoption. Of course it sucks for people who were already using Linux for work and now gotta put up with this shit lol.