I think the line starts to blur as soon as your software uses API calls that are only known to you, the OS vendor, when you use your market muscle in the OS field to attempt to dominate or crowd out competitors in established fields and so on. I don't think anybody would read what I wrote as an objection to the presence of notepad.exe with the windows distribution and I note that that presence never stopped anybody from releasing more capable text editors, in fact I believe microsoft ships such a product themselves at a premium.