Nothing in a third party software suite should be able to defeat Microsoft’s security. So yeah, it was a problem Microsoft needed to fix in Microsoft software. If there’s something grub also needed to attend to, that’s a different matter as far as Microsoft’s concerned.
WSL has no direct connection to the host file system. WSL’s drives are virtualized. Which is a real fuckin peach when you just want to copy things to and fro and end up discovering this 😅