How can he quantitatively determine which debate was more about "substance and policy"? Hint...you can't. His subject opinions about the Republican party are just being projected onto his analysis of the debates. Its as simple as that.
You are right. And you are wrong.
I gave my opinion based on my analysis of the debate, wich is most definiteltly subjective by definitino. But you can objectively determine wich debate is of better quality by fact-checking all the claims for example (as long as we can agree on a reasonable definition of facts in this context). This is a good way to have an informed opinion, even if it is still a subjective opinion. In this area, i believe facts are in massively higher number in the camps of the democrats.
Just to take one example: