Well, if you unwind far enough, I think the original discussion was about why Homebrew has trouble using /usr/local. Where "using" means "owning, adding git repos to, changing permissions on, etc".

OSX suggests /usr/local as a good location to install software, but insists that the directory itself be owned by root, and protects the parent directory /usr under SIP.

My assertion is that Homebrew is using /usr/local incorrectly (and in contravention to all expectation), and that blaming Apple for the problems thereby created is inappropriate.

I also think SIP is a good thing.