It's one thing for them to control US citizens rethoric, but there's very much state-warfare going on and the US is a big target.
Is that an elephant in the room we don't want to talk about?
I feel we're coupling two problems, one of free speech for citizens in their democratic process, and another of information warfare from enemy of the US against it.
Everytime you've got a non US citizen or resident tweeting, retweeting, and other such about US political topics, that's state warfare. Sure sometimes it's just somebody else that cares, but let's not pretend it isn't often time part of state warfare.
Being able to influence the votes for candidates that other states feel will be more supportive of them or would destabilize the US in ways they benefit, that's definitely happening.
Now I don't know if what the DHS is doing is overreach and also affects the internal democratic process, but I really think we should all think a little about how vulnerable we've made ourselves to outside actors.