Making a snide comment is not an apology. @swrobel jumped into a Github issue that was resolved and closed 6 months ago. And instead of taking a minute to read a discussion that agreed with his complaint, went off on a bizarre rant that would be flamed as outright asanine. At least @indirect followed his own CoC and downplayed it as being rude.
there's nothing bizarre or ranty or asinine about swrobel comments. it was venting at a poorly documented API - he admitted as much. is that the most professional thing to do? sure maybe not - but it's not cavalier banter about slavery either. and how about I flip it on you: how about a little empathy for him? if you want contribute to open source this is exactly the kind of empathy you need to have: will this choice make my API consumers miserable.
the apology is very clearly delineated from his comment on the coc.
"Sorry man, I was really annoyed because I was late to this party. I apologize for venting here."
it's very clear and unequivocal.
yes his citation of the coc included a sarcastic smiley. I've already said this: God forbid. reread his response without it. is it still snide? I suspect no.
finally getting back to indirect being unable to take the implicit criticism in stride: if you want to contribute to open source (really anything in public space) you have to be comfortable with criticism. swrobel didn't attack indirect personally (e.g. "you're such a dummy for this design choice") he criticized the choice. that's fine even if it was 6 months after it was fixed (because your mistakes will always be yours - they don't magically get stricken from the record after 6 months). if you are afraid that people will be upset with you for making mistakes then don't make things for people.
Also, I think it's both possible to apologize for my rant and point out that his CoC-waving was absurd.