Except that's wrong, isn't it? Charity wouldn't exist if people didn't do anything out of kindness. Your point "It's legally fine, so it's fine" leading to a "monumentally shit and depressing society" doesn't really stack up against what actually goes on. Your argument is surrounding morality...
I'm almost certain you can ask to pay more, though I suspect those who want higher taxes don't take up this option...
My solution is massive tax reform. Rewrite tax law. Give everyone a 1-2% break, then tighten loopholes so tax avoidance becomes tax evasion. The issue is that the risk-reward...
Then you're opening up the issue of gauging what is morally acceptable, morality is subjective and harder to enforce. You would literally need to engineer how people perceive right and wrong for it to work.