A console cannot be called a PC or replace a PC. It is a lesser category of product.
They can and are, lol, the definition for PC is surrounding the hardware. Whether or not the producer of said hardware has included software locks or hardware locks to prevent you from modifying the operating system on the device does not change that distinction, it only provides justification for closed ecosystems and locking down hardware a consumer has purchased, creating a monopoly over what that hardware can access. Hence why you are being called out for supporting said practices whether you set out with that intention or not. All of the devices you called out run on standard architectures for their computing resources which have drivers and kernels built in more than a couple operating systems already. If the software or hardware locks were not there, these devices would be capable of fitting into the narrowly scoped definition of PC you crafted. As others have pointed out the first gen switch can be loaded with Linux, as can a newer switch once you bypass the hardware lock. As can the ATM which runs windows server. Xboxs/Play Stations could run linux or windows as we have kernels built for ARM architecture, yet they are locked down. Allowing companies to redefine their devices allows them to skirt antitrust laws and parroting those same talking points only serves to reduce your ability to use/recycle hardware you have previously purchased.