His criticism is two-fold: first that it's is too exhausting and doesn't last, and second, that people are irrational and therefore it wouldn't work.
First, Zizek paints direct democracy as exhausting where people are constantly "mobilized" and making decisions instead of living their lives (especially in his case).
The problem with this is that the entire point of direct democracy is to organize society in a manner where people have the most control over their lives. This includes everything from self-managed workplaces to communities. In Zizek's case, being a writer does not require democratic planning, but a workplace, school or community etc. certainly does.
Likewise, the notion that direct democracies "don't last" is misleading because almost all have been violently suppressed for trying. This includes Anarchist Spain which lasted for three years despite attacks from both the fascists and the communists (who were supposedly on the same republican side).
Secondly, the point that people are irrational and need a strong leader to tell them what they want, is almost at the level of Stalinism. Even if we assume that it is true, then the goal would be to just wait around and be saved by the right leader. The beauty of it for those in power, is that no leader will ever arrive to fill the gap and it becomes a self-fulfilling prophecy.
As Noam Chomsky pointed out:
...part of the whole technique of disempowering people is to make sure that the real agents of change fall out of history, and are never recognized in the culture for what they are. So it’s necessary to distort history and make it look as if Great men did everything.The fact is, direct democracy challenges that notion to its core, which is why people like Zizek are against it.
