According to Ben Smith at Politico, Clinton adviser Joel Ferguson said the following:
"Superdelegates are not second-class delegates," says Joel Ferguson, who will be a superdelegate if Michigan is seated. "The real second-class delegates are the delegates that are picked in red-state caucuses that are never going to vo, te Democratic."
I mean seriously, there might be an argument here, but this is just terrible politics. You can attack the meaning of results in states like Utah and Idaho, but seriously it is offensive and silly to refer to their delegates as second-class delegates. The argument for delegates making up their own minds is pretty straightforward. The statistical significance of the population of the party voting in primaries (or even more so in caucuses) is barely representative of the Democratic Party in large. The results are in no way indicative of what party members actually want, but instead represent the interests of an intense subpopulation of the party. Thus, superdelegates provide an importance balance, a way to clarify statistical noise. In many ways, they are better prepared to make a long term decision for the party as a whole.
That said, it was tremendously stupid to make such a comment and Hillary really needs to find a better way to control the comments of her spin people.