Maybe. I've met an awful lot of people to whom such a distinction is just not obvious. People who would, for example, assert with perfect sincerity that MacOS is built on Linux, or that Solaris (or OpenSolaris, or Illumos, etc...) are the same thing as Linux. It may have been a typo, or it may not have been. The person I was directly responding to didn't seem to think so.

Anyway, that's where the sentiment is coming from.