Linux Foundation is a US foundation but Linus lives in the US and is bound by the laws there but depending who wins the vote these sanctions might not matter for long anymore if Putins orange wins.

But he is also still a citizen of Finland- which is bound by very similar EU sanctions. And the Finish police is known to take these things seriously, as do a lot of other EU countries (not all of them,sadly. Hungary and Italy don't give a shit,for example). So if he fucks things up here he might have two major legal targets painted on his back-both the FBI and a bunch of EU law enforcement agencies under Europol can massively hinder his further travel options.

In the end there is a lot to lose for him and Linux(him being persecuted, companies pulling funding from the association) and little to gain(feeling edgy and being applauded by Russian shills)when he keeps these maintainers.

And tbh, from the outside it looks like a fair process was followed.