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.
I'm worried that the answer is "not at all", which seems weird.
"Never Ruin an Apology With an Excuse."
I read Steve's apology and to be honest it was more dismissive and excusing than it was a real apology. So, it shouldn't surprise you that he isn't being cut the same slack you would expect after a sincere apology.
You tell them to roundly go fuck themselves and appeal to the people that agree with you, the opposition's feelings be damned.
The perceived sincerity of apology delivered to someone who is receptive to an apology can indeed be diminished by accompanying it with an excuse.
On the other hand, an apology delivered to someone who is categorically unreceptive to any apology can only be entirely futile. Since there is nothing to gain yet possibly something to lose, the rational course of action would be to not apologize.
Edit: since the latter example seems to be the controversial one, here is a popular scenario in which a significant number of individuals can always be characterized as being "categorically unreceptive to an apology": partisan politics.