In general, Diogenes did advocate against ambition, but that advocacy was largely oriented towards the idea that man is happiest in a 'natural state'.

In other words, Diogenes worked towards freeing himself from slavery, because slavery was not a natural state. Once free, he made no efforts to accumulate wealth or power, because accumulation of such things was unnatural. He wanted to live as close to his 'natural' state as possible - hence the anecdote of him throwing away his water bowl when he realized he could drink with his hands alone.

Reading the transcript it seems very, uh, off-the-cuff rather than a serious examination of Diogenes.