Is there a particular reason you just have to use the "best" product even if it is highly unethical? Why is it not okay to use a product which is better than Go

Is there a particular reason you just have to use the "best" product even if it is highly unethical? Why is it not okay to use a product which is better than Google2010, which we were amazingly happy about back then. In other words, how does ethics feature in your decision calculus?