The sharp criticism of Howard Zinn, and other leftist scholars looks a lot like "basic characteristics" 1,7 and 11 of fascism, as per the article below.
Fascism Anyone?
Laurence W. Britt
http://www.secularhumanism.org/library/fi/britt_23_2.htm<snip>
I will consider the following regimes: Nazi Germany, Fascist Italy, Franco’s Spain, Salazar’s Portugal, Papadopoulos’s Greece, Pinochet’s Chile, and Suharto’s Indonesia. To be sure, they constitute a mixed bag of national identities, cultures, developmental levels, and history. But they all followed the fascist or protofascist model in obtaining, expanding, and maintaining power. Further, all these regimes have been overthrown, so a more or less complete picture of their basic characteristics and abuses is possible.
1.
Powerful and continuing expressions of nationalism. From the prominent displays of flags and bunting to the ubiquitous lapel pins, the fervor to show patriotic nationalism, both on the part of the regime itself and of citizens caught up in its frenzy, was always obvious. Catchy slogans, pride in the military, and demands for unity were common themes in expressing this nationalism. It was usually coupled with a suspicion of things foreign that often bordered on xenophobia.
<snip>
7.
Obsession with national security. Inevitably, a national security apparatus was under direct control of the ruling elite. It was usually an instrument of oppression, operating in secret and beyond any constraints. Its actions were justified under the rubric of protecting “national security,” and questioning its activities was portrayed as unpatriotic or even treasonous.
<snip>
11.
Disdain and suppression of intellectuals and the arts. Intellectuals and the inherent freedom of ideas and expression associated with them were anathema to these regimes. Intellectual and academic freedom were considered subversive to national security and the patriotic ideal. Universities were tightly controlled; politically unreliable faculty harassed or eliminated. Unorthodox ideas or expressions of dissent were strongly attacked, silenced, or crushed. To these regimes, art and literature should serve the national interest or they had no right to exist.
<snip>
Check the whole list out (there are 14 primary characteristics, as analyzed by the author of the article). It is very scary. Characteristic 14?-- Fraudulent elections.