This is similar to recent articles which reported that school voucher programs are unsuccessful. Akin to the blurb in a newspaper movie ad, where the words of reviewers are taken out of context, certain media reported pull-out quotes from the report that were opposite of the conclusions found in the report itself.
You are absolutely correct in your analysis. You saw the contradiction in the Project STAR report yet your voice went unheard. The reason is simple: Government control of a tax-supported monopoly in education is never the solution. The best one can hope for is that the elected politician, and, more importantly, the bureaucrats, will function as the altruistic guides of the education system. Though, even this situation simply replaces the whims and fancies of the consumer with the whims and fancies of government officials. And, the officials can never define the inputs and outcomes desired by the consumer; the system flies blind. What always happens is that money and influence capture the system so that even the altruistic official is lost in the political battles, let alone the realities of government-run enterprises.
You read the Project STAR report and noted the contradiction, yet no one responded in the manner you expected. I would say that the system responded as it always does; money and influence turned a deaf ear on your correct conclusions.
In a system of choice, you would find the operator who runs the school system that matches your desired inputs and outcomes. There would be no worry about the influence of unions or others with conflicted interests. Your voice would be heard.