Which is a company name and a website, not people. A company name listed in this manner does not extend to its employees unless they are acting on behalf of the company; any sanctions against individuals specify the individual's name.
That’s correct. But given that GitHub is a publicly available website, the only way they can prevent employees of that company from being aided by the GitHub website is to remove that company’s code from their website. And because users can create accounts freely without proving employment information, their only way of determining which users could be affiliated is by activity.