Sure, he could certainly say that posting about this was an instance of a lack of discretion (hopefully not on quora itself), but that isn't what he said and what he DID say would certainly be a bit of the pot calling the kettle black with regards to discretion, wouldn't it?

Edit: I still contend you're making a mountain out of a molehill. This kid asked a reasonable questionable in an unreasonable way. He could've avoided a lot by simply redacting the names of the companies; I think we both agree on that. That said, I kind of expect a kid fresh out of college to make a few mistakes with regards to professionalism. An organization hiring those individuals should be set up to mitigate that damage and gently steer them in the right direction, not crucify them publicly. While I expect the occasional flub of professionalism from new employees (and I think on a scale of unprofessionalism, this ranks pretty low), I expect a great deal more from CEOs of corporations with a valuation in the billions. Both messed up with regards to professionalism, but one made a much bigger screw up, and it was the one who I would most expect to behave professionally.