I'm not sure that journalists are that stupid. It's just that the politically correct ones who just repeat what they're told advance their career and the ones who seek the truth usually end up pissing off someone and being censored, harassed, etc.

It's the same pattern we see everywhere in our societies: if you act like everyone else, don't question authority and don't take risks, you won't have any problems.

The journalists you describe are just following the golden rule; make something people want.