Ad-supported services undercut honest ones by pretending they are free when you are paying for them indirectly. They are also incentivized to engage in other bad behavior like gaming SEO or wasting your time with low quality content that's designed to increase ad impressions instead of helping you. I do not recognize the social contract you are implying there is and would be happy if all ad supported sites shut down so that better ones (either actually free or paid honestly) could take their place.