A number of research studies show that in order to achieve the recognized credibility required to be a legitimate or trustworthy candidate for the purpose of appropriation within the news net, individuals or groups attempting to mobilize alternative definitions of the situation are often forced to accommodate or adapt to the narrow confines of legitimized topic parameters.
I think it really means that people who don't share the media concensus of opinion are forced to compromise or adapt their ideas to fit in. It is very hard to read and an example of rather overly dense writing IMO.
