I'm going to give a Marxist economic explanation for why Communist countries don't implement basic things like direct democracy at all levels, freedom of speech, freedom of association/assembly etc.

It's important to have a scientific understanding of why these countries are the way they are. Blanket denunciation of authoritarianism is not enlightening and won't prevent us from repeating the mistakes.

So basically, socialism is about abolishing money and commodity-production. As long as money exists, you can use money to command labour. As long as the state is the source of money, the state can simply print money and exploit people by taking their labour using the free printed money. All communist countries do/did this.

Another source of exploitation is subjective prices. As long as prices are subjectively set by the state through price controls (rather than objectively calculated using labor-time), it's very easy to set up imaginary prices that don't reflect the true amount of work put in by the workers. All communist countries do/did this.

As long as money exists, the salaries are also subjective. Unproductive bureaucrats can pay themselves well without doing any productive labor. The bureaucrats form a pseudo-class that protects its own material interests, which are now directly opposed to the working class.

As long as money exists, you will have a black market. The capitalist mode of exchange can be reintroduced very easily, by simply stealing from factories or shops and reselling. By the 1980s, the USSR had a gigantic shadow economy run by secret black market millionaires who paid off the bureaucrats.

As long as subjective prices are used, it is very difficult to accurately and efficiently plan the economy. If prices do not reflect their labor content as they do in capitalist economies, then it's not possible to decide which investment is truly cheaper. Hence, plans were based on crude quantitative planning of "this many cars" or "that many shirts", rather than financial planning that minimized total labor cost. Financial planning is only possible with objective prices.

The suppression of wages ( made possible as no objective measure of value is used) turns the Communist countries into "sweatshop economies" like those in Africa or Asia. Cheap labor provides an incentive to hoard labor for production rather than removing labor through mechanization, which is what would happen if labor is expensive. This removed a major incentive for economic growth.

Lessons learnt :

1. Communist countries did not abolish exploitation. DRILL this into the head of every single ML or Tankie. They did NOT end exploitation. This is an objective fact.

2. The economic base (exploitation) creates the superstructure ( police state, suppression). There is no practical reason to maintain a police state when exploitation doesn't exist.

3. Ideally you must abolish money and commodity-production. Replace with labor-vouchers.

4. If step 1 is not yet possible/feasible, at least still ensure that prices are objectively calculated based on labor-time, rather than subjectively set through price controls or subsidies. This can be done either by markets("market socialism"), parecon, Lange model etc.

5. The authoritarianism is officially justified through the siege mentality of capitalist oppression and counterrevolution. This is a bad faith argument especially for nuclear armed USSR and NK, who will ever invade a nuclear armed state?

6. Communist countries implemented gun control. This is best and clearest sign of the nature of these states. If there was no exploitation and no classes, why was the state afraid of arming the people?

7. However, it is still a real fact that capturing and retaining power is not an easy task, and that hierarchical organizations have been more successful at this. Anarchists have not yet proven by practice that they are capable of capturing and holding power.