But why the fuck would future humans bother bringing all these people back, even if they could?

There are many valid issues to raise with this bring unlikely to work, but this point seems silly. Why would a road maintenance worker fix a pothole, he's not from around and will never benefit from it? Because it's his job he's paid to do, and he's not having a philosophical discussion about it. Whatever future lab technician will be just going to work in the morning as well, paid by their company, funded by the money the preserved people paid. There isn't much to it.

But it's interesting you said that future humans would kill these people because the preserved people are useless assholes. I'm not that sure you labeled the assholes right in your scenario. Your future humans seem ageist and elitist, thinking only they deserve to live.

There is at least one example I remember from the news of a 20-something girl with cancer being preserved, paid for by pooling money from the family and donations. Unlikely to work but she would have died anyway. So what did she do wrong that she doesn't deserve to be woken up, in your future where the technology is there?