Yes, it does seem that supply side economics may actually be "voodoo economics" as George H.W. Bush once said. As pointed out in the question, studies show Obama's tax hikes on the rich didn't hurt the economy. Those with wealth will always try to keep their wealth, and even increase it. That doesn't mean they are unable to pay higher taxes.
The top one percent of people in this country own more than half of all the money. If that isn't the definition of income inequality than I don't know what is. You can't drop the burden of all the tax on the middle class. The middle class is already struggling as it is. I believe the people with money to burn are the ones who should be obligated to chip in a little more for the good of the country.
Tax hikes on the rich actually stimulate the economy because rich people have more money and can afford to give some of their money back to the goverment. This helps to fund goverment programs and to create jobs, both in the private and public sector. It is a solid plan.
Many countries with the highest GDPs (per capita) in the world employ supply-side economics. Countries like Norway, the Netherlands, Sweden and Australia all have very high per-capita GDPs, and all are essentially social democracies. They prove that supply-side economics can be effective in growing a country's economy. Trickle-down economics, on the other hand, has not been proven to be effective.