The quoted statement, "not a security issue", doesn't appear in the linked page, but via the Thread Prev link[1] I found Daniel Peebles explaining:

> Yes, we did try with them first and they told us they didn’t consider it a security issue, so we posted to oss-security after making sure Apple understood we’d do that unless they asked us not to.

[1]: https://lists.apple.com/archives/darwin-dev/2017/Oct/msg0000...