Well, in part this is a perceptive statement on GP's behalf. After a quarter-century of liberalism and neo-liberalism (from both parties, but especially the GOP), Democrats have been shaken awake by the grassroots of their party to realize that the gap between rich and poor is the greatest it has been in over a century of wealth and opportunity maldistribution. The last time that inequality was this great, we had a progressive era (led in part by that icon of Republicans, Teddy Roosevelt), and a populist movement that was brutally opposed by fed troops.
But on the other hand, one of my favorite (comedic) statements from American "conservatives" is the deadpan remark, "The US is a center-right nation". Well of course it is dummy! There are only two political parties allowed in the US, one in the center, and one on the right! America will change if and when it is permitted to have a full political spectrum, instead of two thirds of one. And don't get me wrong, I'm not personally a supporter of "left-of-center" (by international standards) politicians. But, the influence and impact of having the involvement of a real left would be huge. Even a "tiny" and relatively irrelevant left-of-center party like the New Democrats puts Canada to the left of the US, even though their other two parties are center (Liberals) and right (Tories). This lack of a "real left" is what allows out-of-this-world rhetoric like calling middle-of-the-road Democrats, like the current POTUS the 'S' word. The other effect of that is to legitimize some of the elements of the far left who are often as loony as their opponents on the Tea Party right.
That would make for a good routine on Comedy Central. After all, thats where most of the left gets their talking points.