There is the other side of this much security dependency on U.S. As I said in an earlier post, American military complex comes with a cost of having some war theatre anywhere at everytime. It's not far fetched to say there was some poking by America which Putin found provocative.
It's normal for countries to have ambivalent relations like in this case where there are both pro-Ukraine and pro-Russia sentiments within one country and even families. But it didn't need to escalate this much, there needs to be pragmatism regarding conflict resolution which I think Europe lacks compared to Asia, Africa and South America because of bloated military complex of U.S.