The equivalent of your HP example would be if Canon added something to the camera and lens firmwares to make it impossible to use third-party lenses.
I don't think anyone expects Canon to suddenly update firmware with the intention of making third-party lenses useless. They haven't done that in the past, any malfunctions were down to the third party manufacturers not getting the protocols just right, i.e. they didn't reverse engineer as good as they should have.
RF-mount is no different than EF-mount, F-mount, Minolta A-mount and so on in this regard. Third party manufacturers are free to reverse engineer and develop their own lenses. Canon isn't going to provide them with all the information to get it just right as that would negate a lot of their advantage as a lens manufacturer. Manufacturers who have optioned to license their mounts have put in place certain conditions to protect themselves but they also tend to lack the capacity required to develop and manufacture their own high end lenses in a way that makes a serious impact, or just lack the confidence in their mount at the time (Sony E-mount was a daring experiment that paid off, eventually, but compare that to what canon did with RF or nikon with Z)
Sigma and Tamron have figured out the EF mount pretty good. Figuring out how the EF to RF adapter works should be easy. Making lenses based on that should be no more difficult. And if it is, maybe they just shouldn't be in the business.
Anyone complaining about Canon not simply sharing with Sigma and Tamron every bit of information needed to replicate what Canon themselves are doing is just showing his or her ignorance when it comes to how a business works.