While informal, I do not think his tone lacked civility.
I strongly prefer papers written in this style. Not only are they more enjoyable to read, but they are often easier to understand and more geniune as well. Papers written in a formal style often obscure the real motivation and instead provide a fancy-sounding retroactive justification. It makes the authors feel smarter, and I guess some readers feel smarter as well, but it belies the reality of research.
I strongly prefer papers written in this style. Not only are they more enjoyable to read, but they are often easier to understand and more geniune as well. Papers written in a formal style often obscure the real motivation and instead provide a fancy-sounding retroactive justification. It makes the authors feel smarter, and I guess some readers feel smarter as well, but it belies the reality of research.