I already mentioned two things that would make it a "good" apology:
- Directly mentioning whom you are apologizing too. In some cases addressing a group might be appropriate but in this case it seems like he should have mentioned Casey.
- Directly mentioning what you did wrong instead of phrasing it in an intentionally vague way like "we turned inwards".
Apologies are simple in composition. The hard part is getting over our egos.
In this scenario it really isn't Microsoft who are demonstrating a bleeding ego.
Whatever you think about the apology, Microsoft made it without being called to do so. As an inconvenient data point, the apology (again, whatever you think about it) was omitted from the tweet. Casey blatantly rephrases the employee's words from "could be seen as impugning the reader" to "you are impugning the reader". This is all p-hacking convenient facts into one specific world view, and the fanbase is all too eager to echo it.
All of this drama is great for one specific ego.
My bad that part of the comment wasn't directed at Microsoft, its just something that everyone in general has to face when apologizing.
I do agree that Casey should have linked the apology blog regardless of whether he felt it was sufficient.