Without going into the rest of your points, which seem bizarrely furious at a piece of software, nothing about Homebrew forces you to live inside `/usr/local`.
It is recommended, but if you want to run in `/opt/brew` or `~/brew` you'll get a warning some things may not work but that's it. There's no hard block, and the vast majority of core formulae can pour their bottles anywhere.
Thankfully, none of Homebrew's binaries are stored on GitHub.
Most of the changes committed to Homebrew are formulae-based; of the ~5600 contributors in Homebrew's lifetime only ~430 have contributed to the core code.
SSLv3 is so 1996... Please, please, please with sugar on top, use TLS only. Also there are lots of changes in the software world in the last 20 years, which the SSL codebase didn't keep up with (mainly meaning OpenSSL).