HN often takes the collective position that businesses should be able to discriminate as they see fit, to do business with whom they see fit, and to set prices (e.g. other threads about "price gouging") as they see fit.
Perhaps Github is merely a business doing as they see fit?
There's a difference between HN believing that businesses should legally be allowed to do all of the above, and HN believing that it's socially / morally wrong to do any of the above.
(Note that this is merely a reply to your comment in a vacuum, and shouldn't be construed as me supporting either "side" in this thread.)
My statement isn't actually supporting either side of this thread either, just pointing out that their behaviour seems quite consistent with the things HN has vocally defended with all the zeal of a college freshman who has just discovered "Atlas Shrugged."
And again, there's the belief that someone should have the legal right to perform an action, regardless of whether or not that action is reprehensible.
Ex: You should have the legal right to believe that all green-skinned humans are inferior to blue-skinned humans. But that belief makes you a jerk and I will judge you for it.
"You must do what you think is right, of course"--Obi-Wan Kenobi
But we should confuse how you or I feel with the aggregate behaviour of HN in toto. My observation is that as a herd, HN approves of the legality, morality, and sanity of businesses, especially tech startups, making unconstrained choices that may appear "discriminatory" to others.
I'm not sure HN has ever agreed on anything enough to be described collectively as defending it. I suspect the members of the HN community that defended that viewpoint may be college freshman who just discovered "Atlas Shrugged". I don't see much ground to say, "People on HN sometimes say this, so isn't that the ethos now?"
Perhaps Github is merely a business doing as they see fit?