Because they want to strangle us.
The USA could have made Russia our friend, but thanks to Clintoon, we didn't
That's like saying "The USA could have made fundamentalist Islam our friend, but thanks to Bush, we didn't."
You're not dealing with normal westeners here. You're dealing with KGB/FSB criminals. Mass murderers, thieves, people with ideologies that call for world domination.
The ordinary Russians see their country as a great power, a great force for good (yes, really -- brainwashed, aren't they?) and one whose time must come again.
Putin doesn't want to strangle the USA, he wants two things -- the grander is to have Russia as a respected power, an equal of the USA and the second is to enrich his cronies and himself
He doesn't want to strangle the USA, rather he is like a weak, cornered rat who strikes at what he thinks can "hurt" the USA.