I for one am going through quite a culture shock. I always assumed the nature of FOSS software made it immune to be confined within the policies of nations; I guess if one day the government of USA starts to think that its a security concers for china to use and contribute to core opensource software created by its citizens or based in their boundaries, they might strongarm FOSS communities and projects to make their software exclude them in someway or worse declare GPL software a threat to national security.
Yes. I always thought of sanctions as being finance-related, meaning you can't transact with sanctioned groups. I figured it couldn't apply to decision-making/membership in non-profit organizations (that it might somehow violate "free speech" or some shit). Finding out this is not the case is terrifying and one more reason to hate the US (not that we needed more). This might disincentivize some people to contribute to FOSS.