>To this casual bystander it seems like they usually hurt innocent citizens far more than the leaders of the usually authoritarion regime that it targets.
That's kinda the point. The common folk put pressure on their leaders to correct their behavior.
western people had plenty of time to stop buying russian oil after the Crimea was stolen in 2014, but alas, they wanted to sponsor russian military and police so badly
That assumes the common folk can put pressure on their leaders, which is usually not the case for countries targeted by sanctions from the US, which usually have autocratic or otherwise authoritarian governments.
History is full of violent revolutions against autocratic governments. We should inflict maximum pain on the Russian populace. Be as cruel as possible. Keep the pressure on. Eventually it might pay off. And even if it doesn't work, it serves as an object lesson to other countries on the consequences of opposing US policies.
Amusement has nothing to do with it. This is one method among many for pursuing national geopolitical goals. It's a shame that the Russian populace has to suffer, I bear them no ill will. But if they ever want to get out of international sanctions then they know what they need to do.