I do not think he was that naive. Neutrality worked fine in Austria and Finland for decades.
I think Finland will regret it. And recently, shortly before Finland became an official member of NATO, I heard a statement by the Finnish president that sounded very childish, paraphrase: the main reason for Finland to join NATO is because it will annoy Putin. Not because there is any danger for Finland, but to anger Putin.
And Germany can only dream of such neutrality and sovereignty.
Visibly occupied Germany, so shameful and disgraceful: