Yes, she backed down in response to my comment, which I noticed and greatly appreciated. But she never made any personal admission of fault or retraction to Silas, so I understand why he held a grudge. After all, she did tell him:

If they [women Silas knows] have not invited you to any social functions where you could meet any of their friends, I doubt they like you very much. If you'd like to add a less polite data point, I'd neither date you nor introduce you to my single friends based on what little I know of you.

At this point in the conversation, I really don't see what Silas had done to deserve such as assessment, other than proclaim frustration at his dating situation, and point out that her advice wasn't helpful to him.

If Alicorn had given Silas some kind of personal apology or retraction, admitting that it was premature to try to give him advice without understanding his situation, and imputing negative characteristics to him because of his difficulty accepting that advice, then perhaps the whole communication breakdown might not have happened.

While Silas has handled the interpersonal aspects of their interaction badly, so has Alicorn. I understand why he was frustrated, and felt motivated to point out seeming contradictions between the way she treated him and his arguments, and some of the other posting she did on LessWrong (I also noticed a contradiction between her excellent post on problems vs tasks, and her "let them eat cake" style dating advice to Silas). Along the way, Silas dug himself into a deeper and deeper hole with sarcasm and abrasiveness (despite the urging of me and many others to cool down) and convinced Alicorn and a bunch of other people that he is a jerk, even though he also seems to have made good faith efforts to have discussions with Alicorn on other subjects.

As a result, judgments of Silas by Alicorn or others based on his recent behavior risk falling prey to the fundamental attribution error that Alicorn correctly warns against in the original post. He does have (in my mind) a valid, unresolved beef with a certain lack of charity and hasty negative conclusions that Alicorn displayed to his arguments and character in the past. I strongly, strongly disagree with how he has been expressing it, but he does have a valid beef that people need to realize before piling on him (it's a testament to the failure of his communication skills that he has slowly managed to alienate a large segment of the community even when he started out being in the right.)