This would then leave all those members who had been purged without political representation, or democratic rights. This would then leave those people who still desire a change in the direction of the government with only one recourse - violence against the government. Because it doesn't need to. To do so, would merely risk turning moderate progressives into outright revolutionaries. Capitalism can endure limited doses of freedom for Socialists, limited circulation of newspapers for example.
Capitalism is an ideology with a very shakey grip on the minds of the populace.
Even this ideology can endure limited freedom for dissidents. Surely Communism can endure far more freedom for capitalists. This is clearly a challenging state. This is understandable. But propaganda isn't an all-powerful.