It's a strange age we live in. Any random person may have a blog, and the more subscribers it has, the more "authority" the blogger suddenly possesses. It's like the number of subscribers is proportional the degree of theological authority. If he doesn't have those followers, he remains a random person who posts his opinions on his blog.
This is secular celebrity culture deforming our theology, and in an awful way.
Dr. Chojnowski is free to express his disagreements with the traditional Catholic "mainstream media" (Michael Matt, Ferrara, etc.) with arguments, and we readers are free to evaluate his arguments on their merits. He has the rare position and ability to frequently write on complex topics and bring an extensive set of knowledge and first-hand experience to bear on his analysis. Obviously that doesn't mean he's infallible. Reading and thinking about his commentary has nothing to do with whether Dr. Chojnowski is a supposed theological "authority" or not. Just take a step back and realize you're reading nothing other than an editorial, which is very similar to, I don't know, a forum like this one where everyone can offer their own opinions backed with arguments. The "authority" any of us possesses is irrelevant to the integrity of the content of what we say.
To Chojnowski's credit though, he has a PhD in Thomistic philosophy from Fordham.