Well, the "have to drive on the road" is a "law" or an imperative not an ideology. People know it's a made up convention so that we don't hit each other or depestrians.
People talking about free market, on the other hand, think of it as a real, concrete thing, and even further, that it has this and that properties. Thinking thusly about a made-up thing can have dire consequences -- like when hallucinating on drugs and jumping from a building to avoid a huge snake.
Everything is a made up idea that obscures one's thinking. I think I have to drive on roads, but really nothing is stopping me. I could get through traffic faster if I just started driving on the shoulder, but the problem is if everyone did that it would be chaos, and would be worse overall. Systems have the potential to create a net good.