In topics that are heavily engaged by the media, journalists seek out professionals to provide them with expert points of view on the topic. As journalists often do not know who is considered an expert in a given scientific field, they often contact people in the wrong field for an opinion.
Unscrupulous people will provide inadequately researched information as though it were correct and well-established. The journalists do not necessarily check the information against other sources for veracity, and this leads to misinformation in the public media.