If I ask an "ai" bot to create an image of batman, it does make sense to be modern or take inspiration from the batman of recent, the same applies to information it provides when asked questions. It makes sense to crawl news and websites with copyrighted footers if the information is relevant.
I do totally get their argument and think of the children angle. Getting to the point, it's all about the money, nothing to do with protecting peoples work. They want a cut of the profits these companies will make.
In that case so should open licences demand that they do not make profit from such content. In that case I believe the free AI will be much more useful, if of course people be aggressive back with this tit for tat.
Ads are not the only reason, but if you're still on reddit, you clearly missed the point why reddit became popular.