Without wanting to be confrontationist in any way, and purely as an honest intellectual exercise… would you agree that this very same statement could just as easily be reworded as being about Hitler and Fascism? 
Is there any Marxist state whose leaders did not ultimately end up pitting one section of the populace against the other in a genocidal frenzy? Laos? North Korea? Vietnam? Phillipines? PRC? Albania? USSR? Venezuela? 
I agree with you, it may not be the Philosophy which is directly at fault. All philosophies have their strengths and weaknesses. They are tools, to be used for good or bad.
But different tools are appropriate at different times. Do you see how Fascism is as appropriate to a defeated, humiliated and penniless nation of ‘living on the edge have-nothings’ as Marxism is to a nation with a surfeit of wealth and a glaring divide between the 1% Bourgeois ‘haves’ and the 99% Proletariat ‘have-nots’? To be clear, I support neither.
My focus instead is on causes and effects - how do people get their views so wrong? How do all views end up in suffering, regardless of which end of the political divide we are examining? And what do these ideas lead to eventually?
No matter the ‘-ism’, the key ingredient to retaining power is the ability of the political leaders to turn one set of the populace against a carefully selected ‘other’. Essentially, its about Hate.
The antidote is Love. Mutual Respect. Trust. Harmony. Harmlessness. The ideas upon which the Buddha based his Principles to prevent decline (DN16).
Now what does this all have to do rebuking Julius Evola or debunking the wrong views of Alt-Right Buddhists?
Just as you feel deeply that Marxism is correct and are not really convinced by any of the many attempts that have been made to debunk it or the many rebukes Marx has earned over the decades… in just the same way, Alt- Right people feel strongly that Fascism is correct, and they will not be convinced by any kind of argument that is made against the ideas of Julius Evola, no matter how irrational this may seem to us.
Why is this? Because we are attacking an aspect they cherish as their ‘Self’. The more we push against someone else’s deeply held ideals, the more they hunker down and become unapproachable. Once we stop talking to each other, there can never be rapprochement. And hate breeds more of the same.
Every one of us can however be guided with love to see the negative consequences of sticking to a particular view.
You’ve already agreed that Stalin’s Great Purge was not the best of outcomes. But were Lenin’s Chekists better? Why did Mao’s ‘Great Leap Forward’ lead to the Great Famine? Why have millions died trying to escape Castro’s island paradise? What happened under Pol Pot? What’s going on in Maduro’s Venezuela?
We can put all these failures down to poor leadership for now, if you so wish. Or perhaps you still feel somewhere “This philosophy is Right! Its just not been properly understood or implemented!” Need I point out that that’s exactly how the current Alt - Right feels too?
However, if by virtue of an honest examination of the effects of Marxist Philosophy under the framework offered by the Buddha (MN61) you can see some flaws… then perhaps so can the Alt- Right Buddhists. It is only our conditioning that is different.
We owe it to each other to try. To try and never give up on each other. To agree to disagree, but to never stop communicating.
So why not put aside ideas of rebuking and debunking for now. Put aside Julius Evola. The Alt - Right are Buddhists are they not? The Buddha’s discourses are our common inheritance. Why not engage in a shared exploration of what the Buddha really had to say? Right here on SuttaCentral.

(Views are personal and not reflective of any official forum policy)