It still is not a real democracy; eg ancient athenians were acting (each when his turn came) in most offices of the state. Including as judges. One has to assume that a positive there is that you have to care for others in the demos being ethical and as educated as possible; cause each may possibly decide what happens to you in a trial.
Judges werent as easily bought, cause they were not fixed positions. But the general sense is that you have to care about political life.
Afterall, the english term "idiot" is etymologically the opposite of demotes (citizen) ; meaning one who is focused on private matters.
That said, it was already an issue in Athens of the time, to not care about political life. The main reason plato wrote "the republic" was to argue against apolitical life for philosophers