Google also indexes and returns results for websites that host not only illegal underage porn but terrorism websites, racist websites, etc. and profit from it but we give them a pass? You are making a “what about this??” argument and ignoring that they have mechanisms in place to remove illegal content which any website that allows user-generated content cannot control.
My critique is more about the wide disapproval of the porn industry itself, which you can already see in the comments of this post, which I find both absurd and harmful to the vast majority of legitimate employees of this very popular and mainstream industry.