They are a single issue organization. They have a job to do to protect that issue. Some people don't like it that they do that job well. Others like it that they do that job well.
The are also the 3rd largest membership organization in the United States, behind AAA and AARP. That makes them pretty effective at what they do...which is (i) train people (including LEOs) in firearms use, and (ii) protect the right to defense from aggression of others.
I don't think we have to engage in any Freudian analysis. Their goals are simply stated by them (and referenced in the Constitution, no less), and they pursue those goals tirelessly.