That's one way of looking at it. Another way of looking at it is that leftists and libertarians have differing notions of justice.
Libertarians place importance on procedure, while leftists place importance on results.
To libertarians, if the procedure is just, so is the result. To leftists, if the result is unsatisfactory, the procedure is inherently unjust. Since his salary is the result of a just series of transfers of property, it is therefore just. Unfortunately, it's much easier to identify with a movement's values than to study their facts. The free-market side may have logic and evidence on our side, but since hardly anyone takes the times to study it, that doesn't matter.