They didnt. OP did. The claim is Mac OS comes pre-installed but people don't claim money back for removing it, because it's considered part of the "Mac". With

They didnt. OP did. The claim is Mac OS comes pre-installed but people don't claim money back for removing it, because it's considered part of the "Mac". With windows, people consider it an extra and claim back money for it. At least that's what that explanation was about. They never said Mac OS is "free".