I am not putting words in your mouth. I am trying to understand what your concern is. Every major vendor of Linux distributions maintains their own source tree

I am not putting words in your mouth. I am trying to understand what your concern is. Every major vendor of Linux distributions maintains their own source tree with patches specific to their usage. That is the way Linux is normally used. So what? I don't see how it's useful to say that it's a "modified kernel" due to it being packaged for a specific application in a way that is necessary to use it.