With Google+ you have complete control over who can see how much of your information. The stuff that shows up in search results is no different than if you had searched directly on Google+. These arguments of privacy are misinformed. No one can see your information unless you let them.
Now, about the anti-trust accusations: Facebook has specifically chosen to exclusively share its content with Bing, and not Google. In fact, they go out of the way to block Google from accessing any information from Facebook. Twitter has also opted out of Google search integration. They used to have Twitter integrated into search, but they decided not to renew their contract with Google. How is that anti-competitive?