Their modus operandi is to be the social-development hub of as many projects as they can, and they are successful.

Their platform has lock-in and network effects that you must acknowledge, often being the only bug-tracker available, only mechanism to submit patches and often being the only source of truth for a given repository of code.

Unless you're going to tell me that a private company can do what it likes, in which case I will reignite efforts to put FOSS on FOSS platforms. If Github wants to hold it's market position (made precarious based on their owners and fact that it's backend is closed-source) then they will have to keep good-will.