It means you have been exposed to certain thoughts regarding a subject. For example: If your parents are racist then chances are you are a racist as well through conditioning or indoctrination.

I think "conditioning" comes from a psychology term where a subject automatically reacts to a specific event. In the Pavlov dog experiment, every time a bell was rung, the dogs would be fed. Later, when the bell was rung, the dogs would begin to salivate. I think some people are using "conditioning" as a way of saying how your environment has made you react or think in a certain way. It's sort of like brainwashing -- you've been conditioned to think a certain way. Here is the link to the wikipedia article. (It's pretty technical.) http://en.wikipedia.org/wiki/Classical_conditioning

It means you've been brainwashed.

It may mean that you have been made to think in a certain way. Several person, object or events influenced the way you think about something (you have not mentioned anything specific).