Part of the power of sanctions are to weaken a leader's power over their people. If they lose the mandate to lead, the people may revolt and decapitate the leadership causing the issue.
I agree that they didn't (and still don't) meaningfully care about the people of those countries. The goal of ending socialism was not to help those people (Reagan had a lot more rhetoric about fighting socialism because he cared about the people, but I think like in the Kennedy era, this was mere rhetoric). The people are merely instrumental tools.
You don't have to be pro-socialist or anti-US to believe these things, they're quite well documented.
In 2015 Visa and MasterCard banned all transactions in Crimea. It hit hardest the people who were naturally the least loyal to Putin - the upper middle class, IT professionals, and everyone who relied on receiving international payments. I don't know anyone who has changed their opinion about Putin to worse as the result, but a lot of people, myself included, changed their attitude towards West to worse. And even if sanctions will result in the fall of the regime eventually, you can be sure they will be remembered as a hostile action.
And no, it doesn't actually work like that. If the West does come up with sanctions that significantly affect the quality of life in Russia, the Russian government will simply use it as fuel for its propaganda that the West is out to get Russia (to remind, that's the stated motivation for the invasion!).