Quite frankly, from what I've read (the blog posts only), this seems like a pissing contest that's got out of hand. Each side should back down, stop trying to use the internet to throw poo at each other and work it out. Merge, settle or ignore each other and deal with it when there's a good reason to. Neither of you will lose money if you just compete. I agree with jrockway's points, especially on the sub par brandin…
It seems to me like this was all being done privately until Mr Hamacheck got a lot of attention and the wrath of HN on his side. I don't see how the other founders had much choice but to explain their side - otherwise they look like a cold, heartless corporation. The original story seemed very much like a guy trying to run a business was blindsided by a huge, funded company. But after the response it seems clear that he had been communicating with them and even proposing business relationships before even launching his product.
My opinion of the situation was definitely changed after this response letter. It kinda goes to show that these kind of arguments make everybody involved look bad, though.