Ethics is subjective, the law less so. Most people don’t find GitHub to be unethical so the author will have a hard time convincing people without using the license terms.
Well, that's the exact reason why they wrote this page: to explain to people why they think GitHub is unethical, and maybe convince them. It's the same as calls to boycott various other companies: they haven't necessarily done anything illegal, but if you convince enough people not to use their products/services anymore, you might make an impact...
i think it is quite scary that so many in here would just not honor a simple "please don't do it."
it is a wish. if someone says "please don't wear shoes in my home" i hope you would honor their very simple and understandable personal wish without setting up a contract for it?
My aunt once told me "Please don't think negatively of religious people."
Stallman would prefer I not use any closed source software to read his blog, including OS, drivers, web browser, etc.
People routinely ignore unreasonable requests. Asking me to not wear shoes in your home is reasonable. Asking me not to give a copy to Joe after telling me I can give a copy to whomever I want is unreasonable.
How is it unreasonable to want you to not host someone's code on one explicit other platform?
We already established no one is forcing you and if you don't respect the author you don't get to be respected for your decision to ignore them and will earn snarky remarks. (and rightfully so, in my opinion)
I see it more like an artist telling me “please hang this picture in this orientation” but I prefer it differently and don’t see any reason why me hanging it the way I want in my home affects the author. My copy on GitHub doesn’t detract from their copy.
The author might also be using this a stop-gap until a FOSS licences comes out with similar terms, but don't want to make the current license nonfree because that has different complications.