Well, he didn't say that exactly, but we can infer it from his column. In this piece he again called for President Obama to embrace the deficit reduction plan put forward by former Senator Alan Simpson and Morgan Stanley director Erskine Bowles.
One of the central features of the Bowles-Simpson plan is a reduction in the annual cost of living adjustment for Social Security by 0.3 percentage points. After ten years this implies a cut in benefits of 3 percent. After twenty years it implies a cut in benefits of 6 percent. If we assume that the average beneficiary will collect benefits for twenty years, then the average fall in benefits will be 3 percent over a retiree's lifetime.
Roughly a third of beneficiaries rely on Social Security for 90 percent or more of their income. For these people this change in the cost of living adjustment would be equivalent to a 3 percentage point increase in their income taxes. They would see a much sharper decline in their income than say a person earning $300,000 a year would from seeing the expiration of the Bush tax cuts.
Obviously Friedman does not believe that the cut in Social Security benefits that he is advocating is a big deal. Therefore we can infer that he also does not view the smaller percentage cut in income that would result from ending the Bush tax cuts as a big deal.
It is worth noting that Friedman continually harangues Obama for not doing what he in fact already has done. Friedman wants Obama to be brave and embrace a package involving major budget cuts. Obama has in fact repeatedly indicated his willingness to support the Bowles-Simpson plan.
Given that this plan implies a big hit to many low and moderate income people, and is enthusiastically embraced by DC pundit class, once can question how brave it is to embrace it. But Friedman is essentially making a career out of haranguing Obama to do something he has already done.