I'm sympathetic with those who point out that corporations typically have more leverage than individual employees, and that changing jobs is not so easy for those who are less privileged. That category, though, of "less privileged" with regards to employment flexibility simply does not apply to the average Github employee, at all, as sircmpwn frequently points out.
Furthermore, regardless of which side of this debate you stand on, it is definitely disheartening to see people so vehemently against this relationship yet do NOT back up their feelings with actions. I cannot help but scoff when I see people on Github with "stop ICE" profile pictures. It's nothing but a profound selfishness: wanting to be on the self-perceived "right side of history" but not so much so that you set your origin to Gitlab or SourceHut instead...
For one thing, many have. I would expect that those who remain believe they can continue to exert leverage to achieve their goals.
Walkouts are worthless if you come back to work.
To be honest, I dislike America, and do plan to leave it in the next couple of years. I've always considered it a reasonable option :)
Github from a political standpoint cant drop one govt agency because they stand to lose all their other govt contracts. And any other buyer who now has to now consider they will be dropped if they come down on the wrong side of Github employees' moral compass. Github as a business, especially one now owned by Microsoft cannot do that.
I think Github has tried to do as much as it can to support policy reform without irreparably damaging their business. If that is still not enough employees need to leave at this point. There are many others who would love to work at Github and can reconcile with the situation that Github is in and accept that they are trying to change policy rather than drop the agency and hurt their business.