Further, you don't need a high tax rate. Slovakia is currently the country with the least wealth disparity and is a happy, healthy EU country with a U.S.* / European-like tax rate. The individual income tax rate in Slovakia is a flat 19%.
I don't think anyone is talking about "punish the winners" but about providing true equal opportunity. No one is talking about making everyone finish at the same point, but truly having the same starting line. What Slovakia and the rest of Europe get for their taxes includes universal healthcare and a free (or very low cost) university system -- and those two things alone can go a long way toward a more equitable, and happier, society.
* U.S. tax rates appear lower but when you combine federal, state, local and property taxes, it is similar to most European nations.