Kinda? Whether you like it not that's just how society functions. You either acknowledge what society decides or you end up becoming the guy who argues that drawing swastikas doesn't make you a nazi because it's a symbol of luck.
And if you want to go down the rabbit hole of "PC is personal computer" good luck defining what a computer is without defaulting to what society thinks a computer is, because technically your phone is a computer that is for your personal use. Your phone is a PC. In a sense so is your TV and your gaming console and the steam deck and possibly even your fridge. Maybe even your car.
Save yourself the headache and use PC as you understand it while accepting that others have a different meaning for PC.
You're right. I should've said "the guy who argues swastika isn't just a nazi symbol", because that's essentially what you're saying: PCs aren't just windows machines.
You do know that Android and most modern gaming consoles support kb+m? And I case you want to hang onto to the word "designed", as in they're designed to work without a physical kb+m, then I guess the moment I install SteamOS my PC it stops being a PC?
You're doing the same thing you're complaining about, using a generally accepted definition of a word instead of the actual definition.
So it's okay to misuse words when you also misuse them, but not okay when you don't misuse them? What are you, a self-important hypocrite?