I don't think that he gave too little weight to it as much as he thought a rising tide lifts all boats. He believed the free market was able to solve all problems much better than a bunch of bureaucrats.
Finally, while many may not know it, Friedman made notable contributions in the area of applied statistics and the nonparametric Friedman Test was his brainchild.
> To my mind, his thinking gave too little weight to considerations of social justice <
A distressingly shallow statement from an otherwise near-profound essay.
Friedman thought long and hard about social justice -- just as much as any of his leftwing adversaries, and clearly a lot more than many of them ever would be capable of doing.
But he also realized that government programs generally have imperfections that are fully as serious as the imperfections found in free markets -- if not more serious.
Friedman therefore rejected the left's "default" position that social justice normally is best served by government intervention. And he argued persuasively that in any specific case, the greater "social justice" is almost always going to be found in a market-based solution, rather than in a government solution.
[But on the other hand, it's so refreshing to see Summers partially recant a doctrinaire "government über alles" philosophy that one shouldn't be overly critical!]