It's funny, when I first skimmed the letter I thought, cool, open source Swift. However when I moved past skimming and actually read the letter... wow, it's terrible.
As others have mentioned the first name thing makes the authors sound like some douchey Brogrammers. The rest of the letter is just condescending, snarky or just plain undecipherable and wrong. For example "Swift is a beautiful language but you want to keep it all to yourself. That’s just not on.". They're not keeping it for themselves, they made the language so it's easier for developers to create software and in fact they give away the language/ide/debugger/etc away for free.
"That's just not on." Is this open letter really intended for Tim Cook? Do you think the leader of Apple actually likes to wade through clumsy slang? Have you thought of sprinkling the word "hella" around for more emphasis?
I now view the whole thing as a cautionary tale about the dangers of skimming internet pages.