I don't think you are mistaken.
the author does seem to believe that the DNC is what it presents itself as being: a uniform bloc
it isn't.
a large part of the DNC is an ad-hoc glom of diverse special interests allied by one common mantra: "gimme entitlements". Allied, but in no way truly united or akin. Indeed, many of these special interests would be, in a state of nature, irreconcilable to each other.
the hard part, for me (and presumably for many other non-dems), is to sift out the noise of the glom and see what remains of the DNC. Who are the "real" Democrats, and for what do they stand?
The answer to this question is vital.
The glom cannot long endure. Nor should it, nor, really, should it have ever been condoned or taken politely.
What, then, does "Democrat" or "Liberal" mean, when shorn of the opportunistic parasites?
To be fair, there is some level of confusion over what "conservative" and "Republican" mean.
For me, it is relatively simple: The Constitution (as written by the Founders) is the Holy Bible of my creed; Restricted government is proper; US sovereignty over US soil is inalienable; Federal Law and the laws within any particular state should be consistent and sensible; Let the people do as they see fit, reaping what they sow; private property rights are sacrosanct, etc... The Republican Party currently best serves my creed.
To me, this is POLITICAL conservatism, though it obviously contains within it SOCIAL libertarianism and PERSONAL liberality.
Many "conservatives" agree with me to some varying degree. Many disagree to some varying degree.
I am sure there is some similar range among the Democrats.
But the question remains: What does it really mean to be a "real" Liberal/Democrat?
Again, the problem with premises. It would appear that you assume it's the ideology that binds the parties together. I disagree.
Real Democrats, by which I assume you mean those who are active in the party for something other than business reasons, are an increasingly rare breed. The real Republican is about as rare.
Politics is a business, and divvying up spoils is why most politicos are there.