Leftists are always exceptionally prone to 'project' their own attitudes and motivations onto others. For example, the outrageously and explicitly hate-sputtering media-political elite Remain campaigners in the EU Referendum have been unrestrainedly and repeatedly attacking the pro-Brexit mass majority for running a hate-campaign.
(The fact is that the Remain faction had near-exclusive use of the public megaphone - so there was hardly anything of a 'campaign' - hate-driven or otherwise - of any type for the Leave faction.)
But why are the Left such blatant and unaware projectors?
Essentially because the psychological mechanism of 'projection' is that we use our-selves, our own minds, as a 'model' to understand and predict others.
To a significant extent, and spontaneously (although it can be overcome by recognition and effort): we cannot imagine others behaving in a way of which we ourselves are incapable; and, conversely, we cannot help but suppose that what drives us, drives everybody else.
The paranoid accuse everybody else of their own plotting and scheming; those without motives of altruism assume that everybody else is as selfish as themselves but hiding it; the constitutionally irreligious assume that the faith of others is a hypocritical fake.
But why Leftists especially? Leftists did not always project as much as they do now - the problem is mostly one of the past 50 years and the New 'cultural' Left of 'identity politics'. Nowadays the only knuckle-dragging sexists are Feminists, the only really serious racists are the professional Antiracists; the only significant class warriors are privately schooled and Oxbridge-educated scions of the upper classes.
The reason that Leftists are so prone to projection and can never perceive the fact is quite simply that modern Leftism JUST IS projection. If you subtract the projection from Leftism, there is nothing left over - or, at least, nothing from which you could build a political movement.
So there is no point in pointing-out Leftist projection - no point in pointing-out that the Leftist hate-accusers are the ones who are hate-fuelled - because that is simply how they see the world; that is how things look to them, from inside their minds, given the way their minds work; and Leftists will not stop seeing the world that way until they stop being Leftists.