Most of what you said is exactly my point. It’s true the word Linux, used properly, refers to a kernel and not an operating system. But that’s not the way the word is used in practice, and it is not what OP meant when they used it. They meant " an OS with the Linux kernel and GNU userspace utilities." When the word Linux is used that way, Android is not Linux.
GNU/Linux != Linux
Linux is a kernel
GNU/Linux is the GNU userland (tools and libraries) combined with the Linux kernel to form a complete operating system
Android is Linux but not GNU. So are Alpine, postmarketOS, and others I can’t think of
Linux is to an operating system as bread is to a sandwich… an essential component, but a slice of bread by itself does not make a sandwich make
I feel like that’s precisely the point they tried to make
Most of what you said is exactly my point. It’s true the word Linux, used properly, refers to a kernel and not an operating system. But that’s not the way the word is used in practice, and it is not what OP meant when they used it. They meant " an OS with the Linux kernel and GNU userspace utilities." When the word Linux is used that way, Android is not Linux.