Oh and how do you intend to solve that most "communists" leaders were fake and intended to become dictators from the very start. There's many cases of various dictators, from anarchist, to just self-interested people, fascists, religious lunatics, ... pretending to be communists to grab power. In many cases, communists supported these awful people with extremely bad results. Examples: Russia, Afghanistan, Iran, Poland, Venezuela, ... all are cases of communists supporting would-be dictators that had ZERO intention of ever making those societies equal or tolerant or democratic.
In fact there's plenty of people who got support by pretending to be communists, even going so far as committing terrorist attacks on behalf of communism, to turn around and become capitalist "leaders", like ... well, most of the members of the EU commission for example. Jose Manuel Barosso, for example, was part of communist protests that lynched people. He was also the EU commission president that pushed Greece into debt servitude.
Not necessarily the first cancer, but eventually one will.
Cancer is when a component of a system acts to replicate or enrich itself instead of acting to perpetuate the system.
But for states, they still feverishly cling to the idea of unity even as it brings increasing fragility and stagnation.