It's a fair set of questions, posed fairly directly, without any sugarcoating. If you read it as a ruthless critique, it stings. If you read it as constructive

It's a fair set of questions, posed fairly directly, without any sugarcoating. If you read it as a ruthless critique, it stings. If you read it as constructive feedback, it can bring the author a lot of value. If the author can clearly show the value proposition of their library, it will get more adoption, and the community and the author will get value. If the author realizes they coded something that is already a well-solved problem, or a poorly-constructed alternative, the author and Nike could gain by throwing this away and going with a better alternative. Personally, I wasted too many hours of my life creating a solution that did not solve any problems. Had I done some thinking and/or market research ahead of time, it would have saved me ton's of time to work on more worthwhile endeavors. Good feedback is worth its weight in gold, even if it hurts a bit to hear it.