The idea that a single public exhibition of a work is enough to invalidate any future sale of that work is totally silly. Are you gonna bust out the window of a Barnes & Noble because libraries exist?
It’s exactly the same. You give access to an entity that serves to promote your content. The fact that Google’s cache is accessible is a technical implementation detail; Google could remove access to that cache tomorrow and that wouldn’t change anything.
It's intentional to fix the kind of abusive behavior you are engaging in. If you serve content to a search engine, that search engine will reproduce the content.
Search engines are for publically available content.
If you want to advertise, pay for it.
The difference is consent.
Google is obeying robots.txt. Google caches a copy of what you serve and gives that out. That is part of the deal.
I don’t get this. They do whatever they want with their content. Editors give free book copies to journalists; that doesn’t gives you the right to have one as well.