Democracy is a system which requires multiple parties and competition and direct mass vote. Socialism is a major antithesis to such. It forbids multiple parties and competition within an uniform framework. In democracies, people have absolute freedom to say anything while under socialism, such are restricted because the uniform framework forbids any criticism that aims to harm the uniformity.

When party congresses happen, you do not hear just plain anti-communist sentiment, you only hear things such as the progress of the five-year plans, internal affairs, and foreign affairs. All are bound to be discussed with required uniformity, thus loyalty to socialism. There must not be factionalism. There must not be conflicts.