That's true, and when Google started extracting information from web pages and displaying it in results pages without driving any traffic to the original websites, the authors of those pages were justifiably upset.

Google Search is ethically acceptable because for the most part website creators like being in search results and are "compensated" in the form of more visitors, and if they don't like it they can easily exclude themselves. Website creators famously do NOT like it when Google indexes their content and then serves it up independently.