That vote was meant to be an insult to the US. It mocked the vote congress took to authorize the invasion of Iraq. They cited the threat to Russian people and the homeland. It was taken after 2000 troops were already in Crimea. Putins [Bleeeeep!] for tat.

I hope we're not in range to shoot 'em on sight, though.
It's Russia's backyard, they are going to do as they please... just as we would.