The data on the use of the filibuster is pretty straight-forward.
The Rise of Cloture.
Besides, the whole point of the article was to dispense with bias... the bias against appearing to favor one party over the other by pretending that the tactics and policies of both parties are perfectly equatable in every way. That's just silly.
The Republicans are fighting more aggressively than the democrats, and the result is that nothing can get done in Congress. You might applaud their fortitude, but there is no reason why it should be off limits to point out that the gridlock is largely driven by republican fighting tactics.
And it also seems pretty clear that, as a party, Republians have shifted further to the Right, while the democrats have shifted closer to the center. Again, why should we lie in the name of fairness and say that both parties have polarized, when really, only one party, as a whole, has done so?