There's also the fact that later on if your kid wants to certain things, either as a hobby or just with their friends, they're SOL because they don't run on Linux and the FOSS alternatives are awful and would scare them away. Kid wants to play a game with Kernel level anti-cheat with their friends? Nope doesn't work with Linux, unless they want to risk getting banned. Want to try your hand at video making? Good luck using obscure software that may or may not spontaneously crash on you and getting cameras to talk to your computer properly. Get a new toy that talks to your computer? Ha ha nope in your dreams

Sure you might be able to fix those problems, but can your kid? Can your kid do these things by themself and foster a sense of understanding and mastery over Linux, or are they going to grow up thinking that they can't do anything on their own computer because they constantly have to call over their dad for help?

Growing up my house was a Linux household and the first thing I was taught how to do was how to dual-boot into windows because letting me play The Sims and have fun was a little more important than ideology wars