I believe everyone here is talking past each other. Decentralization doesn't just mean hosting. My copy of git repo is equally as valid as yours. Or, the master branch is nothing special, any branch is equally as important. In that way, it is decentralized.
But, as you're saying, rightfully, hosting of the remote repository is in the hands of Github. So its not decentralized.
These discussions tend to be like the ones involving 'conciousness'. Until a clear definition of the term is agreed upon, it is impossible to talk about it. Going around measuring with a yard stick requires that the stick is calibrated to a yard and everyone agrees it is a yard. May be you can do some probabilistic measurement (consensus of people whether something is decentralized or not), but it's pretty useless.
But, as you're saying, rightfully, hosting of the remote repository is in the hands of Github. So its not decentralized.
These discussions tend to be like the ones involving 'conciousness'. Until a clear definition of the term is agreed upon, it is impossible to talk about it. Going around measuring with a yard stick requires that the stick is calibrated to a yard and everyone agrees it is a yard. May be you can do some probabilistic measurement (consensus of people whether something is decentralized or not), but it's pretty useless.