This particular phenomena is what I call information disease. (Note: link is not safe for work nor for those of a delicate constitution.)

The human mind filters new information through the prism of the information it already contains. If enough ‘diseased’ information is fed to the mind, and the functions that judge that information are damaged or repressed, all future information is rejected or damaged by the mind. The disease becomes self sustaining.

It’s a scary, common and unfortunately unrecognized problem.