So it's impossible to create a somewhat standardized interface to load virus definitions without directly accessing the file system and loading files directly into kernel space? I find that hard to believe.
I am fully aware that all software sucks. It is just that some software sucks less, Linux is not perfect, and indeed the state keeps getting worse, because a lot of software is written without any thought for security. There is this D-Bus monstrosity, where absolutely nothing is documented. And all sorts of data is dumped into it, with no regard for privacy. There's this systemd thing that keeps pushing its tendrils into everything, and indeed that was the crux of the xz thing I mentioned earlier.
But with Linux at least it is possible to find out about these things, and to change them. With Windows, you have no choice but to accept the state of affairs you find. You have no choice but to accept the statements from Microsoft, that Windows is insecure and must be secured with "security" products, and that there is nothing else that can be done to help. And that there is no keylogger in Windows that is phoning home, honest!
You seem to be laboring under the misconception that I see the world in black and white. I don't. I try to look at things evidence based and rational. And from a rational point of view, using closed-source software, trusting only in the words of a company that is motivated by greed and greed alone, is insane.