Did you read your own link? Deplatforming has been used for decades, by the right wing as well as the left:
> The University of California, for example, had a policy known as the Speaker Ban codified in university regulations under President Robert Gordon Sproul, mostly, but not exclusively, targeting Communists. One rule stated that "the University assumed the right to prevent exploitation of its prestige by unqualified persons or by those who would use it as a platform for propaganda." This rule was used in 1951 to block Max Schachtman, a socialist, from speaking at the University of California at Berkeley.
> The University of California, for example, had a policy known as the Speaker Ban codified in university regulations under President Robert Gordon Sproul, mostly, but not exclusively, targeting Communists. One rule stated that "the University assumed the right to prevent exploitation of its prestige by unqualified persons or by those who would use it as a platform for propaganda." This rule was used in 1951 to block Max Schachtman, a socialist, from speaking at the University of California at Berkeley.