Palm oil is used in many products. About half of food products use palm oil. It is normally listed as vegetable oil. And yes, people should try and reduce their use of it. The reason why it is used so often is probably because it is cheaper. It helps companies to maximize profits...which is all that matters...right?
There are sustainable sources of Palm oil. If you are going to use it try and make sure that it is sourced from sustainable methods.
For example nutella is made with palm oil but they are one of the few companies that sources their palm oil from sustainable sources.