Couple of things:
American citizens can afford those lavish lifestyles too, the money isn't lacking because we spend it on defending Europe. I know that's a super convenient and easy to understand chain of causation, but I encourage you to think a little deeper.
You're right, let's not be allies with Europe. Putin will keep his hands off. Besides, wars in Europe pretty much NEVER turn into big deals where tens of millions of people die right?
In all seriousness, fuck people who talk like this. Those people are our fucking allies. This is not a joke. We have sacrificed millions of lives and untold treasure together to defend democracy. We have a bond that stretches back centuries forged in blood and common purpose. This is not something we get to just walk away from. You dishonor every American that died to protect this alliance and you turn your back on the ideals that are at the very core of our existence. And on top of that, you piss on the contributions of our allies, who sacrificed their share to maintain peace, despite what most Americans like to believe.