Horowitz demonstrates that a left wing world view is not compatible with intellectual honesty.
I don't know what you mean by that remark. Although Horowitz's youth and young adulthood were devoted to "a left wing world view" (he was admittedly a Red Diaper Baby), he left his former comrades on the left decades ago and has long been a bona fide conservative, especially with respect to staunch anti-Islamist, anti-jihadi positions.
It's Horowitz's current detractors on the left, such as the hecklers present at the speech described in the current article, who have a problem with intellectual honesty, as well as civility.
or freedom of speech