I'm no fan of ICE – a very large percentage of my friends in the US are immigrants, and I generally want my country to be a welcoming one. ICE has certainly committed unethical and probably illegal acts (probably true of most federal agencies).
But to expect that a _federal agency_ will be denied service from a private entity, especially for essentially political reasons, is lunacy. It'd attract extreme negative attention from the rest of the government, and great fear from all paying customers that an internet mob could separate them from their code at any time.
We should absolutely be lobbying hard for changes to immigration law, the restrictions placed on ICE, and justice for their wrongdoings.
But I can't see how this helps improve immigration, and it certainly seems likely to cause a lot of negative consequences for GitHub. The employees are putting their employer in a "damned if they do, damned if they don't" situation.
EDIT: Just to clarify, I love the vision of a world where executives don't take actions their workers will protest. I think that in order to get there, the protests need to be reasonable, and I think this one isn't.
EDIT DISCLAIMER: I own a small amount of MSFT stock, which was not on my mind as I wrote this. I use GitHub's free service and have no other relationship I can think of with MSFT or GitHub.
Um, think you've got this backwards. Private entities shouldn't have to take on anyone they don't want as customers (for whatever reason - do you have to justify who you do or don't want in your livingroom?), but publicly-funded institutions shouldn't be able to deny service on political grounds.
In free societies, governments should only be able to forcibly compel people not to do things (murder, threaten, steal, etc.) - see the concept of "negative rights."
If, like a significant portion of the HN audience, you are straight, white, middle class and male it's probably easier for you to dismiss the right to fair treatment than it might be for individuals in those categories.
Segregation wasn't a case of the government pushing these ideas on to unwilling populace.
White parents were more likely to be able to afford to move which resulted in them leaving. Minorities tended to be poorer and could not leave and stayed in the areas with the worse schools. Kids who go to worse schools are less likely to get out of poverty so they stayed in the same poor areas and had kids in the same area repeating the cycle.
Since schools are typically given money based on property tax it meant that the schools in poor areas tended to receive less funding. There are also issues with teachers getting lower pay if they were in a poorer school. I think these issues are fixed in some states but there are still issues related to this in various states.