There was a definite lack of understanding about what that relationship is in that statement.
That relationship is based on the fact that Microsoft embeds a security key in the UEFI firmware implementation in most, if not all, MB makers. The intent is to ensure that the Microsoft OS installed is genuine. To me that's a reasonable concern, considering the jealousy that MS has for its OS. That intent often times has created difficulties for non-MS OSes in that the UEFI implementation may, and has at times, prevented the OS (i.e., Linux) from booting.
Rather than do battle with MS, Canonical and perhaps others have inserted a security key into the pass-off between the UEFI firmware and the boot sequence of the Ubuntu OS. Yes, with most UEFI implementations, it is possible to disable Secure Boot - in fact MS WANTED that capability. But by inserting the Canonical security key, based on the MS key and chained with it, it is possible for Ubuntu/Ubuntu derived OSes to boot more cleanly, but the Canonical key is not required for a successful boot.
While I have no particular love for things MS, what Canonical did in "partnership" was to make it easier to boot in the UEFI environment. And that would be to your advantage and mine, but is in no way a requirement for use of Canonical Ubuntu or its relatives (i.e., Linux Mint).