The vote was very close in Norway, IMO not joining the EU was about as big a mistake as the UK leaving the EU. The no campaign was mostly based on lies and fear that Norway would lose its oil.It is an important principle, supported by most small and also many medium sized countries.
In Europe one has worked hard to honor this principle. Norway decided to not join EU -- this choice was respected by EU, and peaceful negotiations led to agreements that both parties benefit from. Sweden decided to not join NATO -- this choice was respected by NATO. The UK decided to leave EU. This choice was respected by EU, and peaceful negotiations led to a "divorce" that both parties agreed upon.
I fully agree that we should work harder to limit unwanted meddling in other affairs also from the US and others. The same rules should apply to all. The excuse that "somebody is doing bad things therefore I can also do bad things" is however a horrible excuse.
Also not sure why you refer to Ukraine as "special" -- the reason why the Baltics, Poland, Bulgaria, Romania, Hungary, etc. all wanted to join NATO was to reduce the potential for Russia to drag those countries back into Russia's "sphere of influence".