That is not how anyone uses that term. For starters, Linux is also GPL licensed, so if it was like that then we wouldn't bother calling it GNU/Linux, we could just call it GNU. More to the point though, being GPL-licensed doesn't make something part of the GNU project.

"GNU" in "GNU/Linux" isn't about the license but about the GNU OS, https://www.gnu.org/gnu/gnu-linux-faq.html#why