Wealth redistribution and the middle class?

Consider medicare, medicaid, and social security. Since these programs were founded, our government has probably redistributed the entire national GDP of America (just a guess). But the timeframe is what's really interesting. Seems like since the 60s (Medicaid was passed in 65), every year more and more wealth is redistributed, and the middle class keeps getting smaller and smaller. I think it's safe to say the middle class wasn't shrinking until after wealth redistribution became the status quo. So why do many Dems insist that wealth redistribution is the solution of the shrinking middle class, instead of the cause?