Of course, I quite agree. One ought not to over-state the resemblances. But I always find it interesting to consider the meaning of 'skepticism' in regards to both the ancient Greek and Indian schools. Nowadays we think of 'skeptics' as being kind of anti-spiritual or at least basically 'naturalist' in their outlook. But a really deep skepticism is actually a sadhana
. The same for the original 'cynics'. They too were basically like renunciates. But the meaning of 'cynic' has also changed over time.
Anyway, I know that it is tangential to the main thread. Take it as a footnote.
Learn to do good, refrain from evil, purify the mind ~ this is the teaching of the Buddhas