I still don't understand why foreign influence is regarded as such an intolerable threat.
Disinformation is the real danger, and it should be equally concerning whether it comes from without or within.
I mean, among other things, if they break laws in the process we don't have the same sort of jurisdiction to kick them for it. Similarly there's fairly unique pressures involved that don't exist in regards to domestic influences (see fucking ukraine for a recent example), or at least involve different issues or means of preventing or punishing misbehavior.
Beyond
that there's issues of transparency and whatnot that we value for goddamn good reason. Shit could probably keep going in that direction. Domestic issues probably are more important, but that doesn't mean foreign nationals (and literal intelligence agencies) running disinformation campaigns and related horseshit is somehow unimportant because of it.
Much of the rest of it just standard non-locals-can-fuck-off-from-our-local-decision-making stuff you see every time some jackass from out of town tries to run for office or whatev', just expanded in scope. Probably xenophobia adjacent, but it's not entirely coming from there. You legitimately want to reduce the influence of fucks that aren't directly involved and may have reason to actively undermine your group's (town, nation, commune, whatever) general wellbeing. There's a similar sentiment in wanting out of town megacorps to screw off when they're trying to predate on your home town or whatev'.