Kipnis clearly doesn't think much of the Ewell paper, but I don't think her point centers on its contents; it's more that someone collected and published scholarly responses to the paper, and the social media pushback against these responses led to a grad student narcing on his professor and the professor losing funding, the journal, etc. That, to me, is not a healthy dynamic for a university to run on.
edit: Actually let me go a step further and agree with you a bit - I think Kipnis's point would be more clearly made if she didn't make her own perspective on the merits of the Ewell paper such a big part of that section of the article.
AIUI, a lot of the pushback on those responses was due to how they were collected and published. The call for responses was mostly circulated privately among pro-Schenkerian scholars, and the broader profession only got to know about it at the last minute. And the author of the original paper was given no opportunity to provide a rejoinder.
I'm not even sure that the actual written paper had even been published at that time: the basic arguments of the paper were first summarized in a conference presentation, and of course it is terrible form to publish a purported critique of something that hasn't even been fully presented in full detail! The whole thing has really reflected pretty badly on the authors of these 'critiques', for very good reasons overall.
edit: Actually let me go a step further and agree with you a bit - I think Kipnis's point would be more clearly made if she didn't make her own perspective on the merits of the Ewell paper such a big part of that section of the article.