It all depends on how you look at the overall system Google has created. If one considers the entirety of Google+ to be a mere component of Google Search (like the now-extinct Friends section of Netflix was), then one can better reconcile this situation with supposed fairness. After all, what's to stop Bing or Yahoo from creating a social component to their products which affect search?
So the issue in is not one of ethics, but of how Google is marketing Google+. When all that existed was the +1 button, no one complained about ethics. Nothing has changed since then except a reworking of the information architecture of the same +1 data and processes. Google seems to believe that Google+ needs to exist independently of Search. If they're gonna stick with that route, they need to open the Search platform to 3rd party integration.
So the issue in is not one of ethics, but of how Google is marketing Google+. When all that existed was the +1 button, no one complained about ethics. Nothing has changed since then except a reworking of the information architecture of the same +1 data and processes. Google seems to believe that Google+ needs to exist independently of Search. If they're gonna stick with that route, they need to open the Search platform to 3rd party integration.