There is a glitch in the web page because the macOS link doesn't provide any package to download.

The problem is that the announcement page goes to [1] where it should go to [2] (a simple issue using os=macosx instead of os=macos)

brew install --cask factor also works

[1] https://builds.factorcode.org/release?os=macosx&cpu=x86.64

[2] https://builds.factorcode.org/release?os=macos&cpu=x86.64