A lot of families already have a Windows computer and not everyone can afford a spare computer to run Linux on, and some people's PCs can't run a full Linux in a VM either.
Windows has a lot of ways to develop for Linux/Unix now. It sure isn't FOSS, but let's not discourage a promising way to get more people into software, even if it's on Windows.
The "installing" part is the problem here.
I installed Manjaro XFCE in my parents' old PCs, and they're now enjoying it. They never did it because they didn't know how to and didn't want to destroy their already working, but slow PC.
Teach that, and I'm pretty sure everyone would love the customizability that the world of Linux provides.
Windows has a lot of ways to develop for Linux/Unix now. It sure isn't FOSS, but let's not discourage a promising way to get more people into software, even if it's on Windows.