(Disclaimer - I haven't read up on this subject).... but surely if you are technically competent at re-installing a brand new OS (like Linux) onto a machine, then you are technically competent to go into the BIOS/UEFI options screen and disable secure boot? (Assuming the board vendors provide such option).

I'm also curious - are the FSF fundementally opposed to secure boot? What alternative solution are they proposing to thwart this type of attack vector?