Giving your signature is never useless on things like this, as it is direct increase in the total support. The more the threshold is surpassed the harder it is to dismiss a moment as and activist fringe and not mainstream opinion.

Whether or not they are US based entities I think is moot since several developers have already been booted from kernel development due to their affiliations largely at the behest of the US.

Also if they try prevent downloads it would have the interesting side affect that: all the folks out there seeding and torrenting Linux ISOs might have to now also claim they only share the un-embargoed ones, wink.