He's plainly wrong. Leftism in the imperial core is largely reformist of capital. Economism, essentially; prostrating and asking the bourgeoisie for a far less brutal crack of the whip of oppression and a slightly wider sliver of the "imperialist plunder" pie. They have no internationalist solidarity (excepting the PSL, who openly embraces international solidarity with the global South). They think of reality only within the confines of their national borders, neglecting the global role that their imperialist nations play. Without the rest of the globe to exploit, the nations they know would not exist. But they somehow want to strip away all of the external and somehow create an accurate reading of reality. They arrive at nothing but distortions and their failure after failure is testament to this. Meanwhile, the bourgeoisie knows precisely what drives the engines of capitalism; at this moment, the Western left is nothing but an insignificant pest buzzing in their ear.
Once the left learns to break from the capitalist, opportunist, and revisionist elements that inhibit the necessary revolutionary development of its proponents into an internationalist front to combat the global engines of oppression, then will they really experience the brutal reality of the global South that they've been so coddled and separated from. Only until leftists are massacred in the hundreds and thousands by the bourgeoisie's fascist lapdogs within the imperial core will they understand that this brutality must be met with a far stronger, unrelenting, and less forgiving violence. They will know that the only way to truly root out the bourgeoisie and their fascist servants is in the most vicious and thorough fashion.
All of the revolutionary movements and revolts of history, whether successful or crushed, will be vindicated when reality reveals to those in the present the true, naked nature of the neoliberal death cult that has held the world in subjugation for centuries.