To be absolutely clear, we don't know shit what Socrates thought of Democracy. Socrates wrote absolutely nothing down. We do know what Plato thought of it though, since he is the author of all the dialogues.

Moreover, Plato came from a wealthier, more prominent family than Socrates and he had family members on the side of the Tyranny of Thirty or whatever they called themselves, anti-democratic revolutionaries that claimed governance of Athens for a few years and weren't terribly liked.

He hated democracy for the same reason everybody hates democracy: people cast votes contrary to his. Anything else is (how you say?) sophistry.