I think the opposite is the plan: Fearmongering against the EU with false talk of sovereignty to butter it up to be eventually be swallowed up by the US.
Greenland wasn't at risk of invasion either, until the US explicitly started threatening it.
It's not the Russians these places need to worry about. Sovereignty will go away either way. The question is whether democratic rule will stay or not. It would as part of the EU. The US has precedent not granting it.
Your point of view is fundamentally anchored to the world of yesterday, when the global landscape looked significantly different and the US was a guarantor of security to Western states, not a threat model. The world has changed since. Old assumptions no longer apply.