@Dianora The only conclusion I can come to is that, however questionable the person behind the idea or creation is, the idea/creation itself has a life of its own. If it has merit or worth or utility, it has to be assessed independently.
I was deeply shaped as a kid by Ender's Game, for example, as it taught me to extend empathy to encompass the "othered", even when it's hard to do. As an adult, I found out -- irony of ironies -- that the author is an awful, bigoted person who fails to do that very thing with his fellow real, living human beings. That doesn't erase the positive ways I was shaped by the book. It just makes me want to never purchase a copy again and thereby fund his bigotry.