You're making the mistaken assumption that the people who need to think critically have all of the information or even the right information to do so. Most people are making judgements and coming to conclusions based on less than whole data. They don't have time to exhaustively investigate everything about every topic and make sure that all of their sources are flawless. You're asking for perfection. It's impossible.

This is not reasoning for censorship by the way, its reasoning for systemizing trustable sources of information. Someone will care enough to get it right and fair so we should promote them and ignore the others.