Well, first off, ignorance, selfishness, and susceptibility to manipulation aren’t fixed traits, they’re produced and reinforced by hierarchical systems - states, corporations, mainstream media, etc. In other words, people behave the way they’re incentivized and conditioned to behave. Luckily, even if people are stupid and selfish, this system has a lot of safeguards, far more than representative democracy. I’ll explain:

A consensus-based decision making system does a great deal to prevent these issues. Under representative democracy, individuals have almost no influence. They don’t necessarily have to engage with - or even hear out - the opinions of everyone in a discussion. Political engagement is very low under representative democracy, but under a consensus system, necessarily, people need to engage to participate.

That engagement would mean that people have to hear out all voices in a debate, so they’d inherently become more informed on the facts. Additionally, this approach also adds social responsibility, since you’re not just casting a single vote, but need to confront your neighbors and discuss with them, meaning selfishness would also be counteracted through that social accountability.

Finally, anarchists are in favor of decentralized decision making. Instead of one big system where half the population can mess things up, anarchists work to build many small, autonomous groups, which are loosely coordinated and work together, with decisions made locally and then bubble up, rather than made centrally and imposed down. That way, even if one group makes bad decisions, it doesn’t drag everyone else down