Yes, because Homebrew's practice of installing packages runs contrary to the requirements of a multi-user system.

MacPorts is sponsored by Apple, or at least used to be.

MacPorts was originally started as DarwinPorts as part of the OpenDarwin initiative at Apple [1]. Apple continued to sponsor MacPorts by providing hosting of website, repository, and build servers at Mac OS forge [2] until it closed back in 2016. The project then moved to GitHub and their own servers.

[1] https://trac.macports.org/wiki/MacPortsHistory

[2] https://www.macosforge.org/

TBH it's weird they haven't built their own

They did: https://trac.macports.org/wiki/MacPortsHistory

I'm not sure why you are getting downvoted. I'd not like it if Apple will opinion-ate and make any package manager a default.

Package managers are for software developers. They are comfortable installing them on their own.

I expect he’s getting downvoted because he doesn’t offer any reasoning (or substance at all) along with his opinion.

The reasoning was in the question itself. Sometimes a prompt answer is a better one.