Stalin got stuff done. Under his rule, the Soviet Union underwent a change from an illiterate agrarian poorhouse to a wealthy industrialised nuclear power, a transformation that, despite interrupted by the Nazi invasion, is legendary and to this day unparalleled in the world in terms of speed, scale, scope, and thoroughness of execution; along the way creating masterpieces in all fields of human endeavour, founding an immense scientific apparatus, developing the culture of the individual republics, establishing diplomatic relations with the whole world, winning the Great Patriotic War, and setting the global order for decades to come. No leader in human history can claim to be his equal.
This means he, and much more importantly, his philosophy and economics, is inextricably tied to the international left, and to keep him down is a necessity to keep us down. If anyone espousing his teachings were to lead another major country for an extended period of time, it would be a disaster for the bourgeoisie, not only in the West, but the world over. His combination of Marxist-Leninist philosophy, large-scale and long-term central planning, and a political emphasis on developing science and technology has proven lethal to global fascism back then, and it will prove lethal to global capitalism next time.