I think the OP is true, most of the time, whether people want to admit it or not. However, there are times when it is not. For example, there are moments when a person must act quickly, without thinking. In many cases, there is not time to think even on what you are about to do when you are helping someone. In cases such as those, there is no denying the altruism behind the act.
(Sociopaths do not help others for no reason. It is kind of part of the definition of sociopath.)
(Sociopaths do not help others for no reason. It is kind of part of the definition of sociopath.)