I think it comes back to politeness, somewhere in amazon there is product manager that saw or was shown Tim's repo and saw an opportunity(nothing wrong with that). It would have been a nice thing to do to give him a shoutout just like it was a nice thing to do of Tim's to release his code under a permissive license. There must be a mountain of code forked by large companies that if given some sort of recognition would be of benefit to the original author even if its only internet points.