Very juvenile and unprofessional way of dealing with the situation, really erodes trust in the platform (simply deleting the comment would have been a better response).
Would maybe expect this from the founder of a young fledgling startup, but the 33 year old CEO of a company like Reddit ought to know better.
If I read this Reddit thread without knowing him, I would have deemed him unprofessional and maybe even upvoted some of the comments.
When I read the thread knowing who he is, I'm thinking "I can't imagine how stressful it must be to run Reddit. He made one mistake in a bad day, apologized for it, and now everyone's talking about it. Steve's way nicer and more professional than I am, so I would probably have messed up big time in his shoes."
If it was a mistake resulting from inaction one could attribute that to stress.
This was deliberate action. I assume/hope that this special mode of editing (without the "edited" asterisk signifier) isn't just the default "edit" button Spez gets for every post if he's logged in, but that he had to jump through a few hoops and "are you sure" boxes to get there (or maybe was it direct DB editing).
There's some things you just don't do with admin powers, lines you don't cross, not even for shits 'n giggles. And apparently he doesn't truly believe that, because the amounts of stress that would make one cross those lines are way beyond ability to function as a person, let alone CEO of Reddit.
I think you misjudged his professionalism.