Answer:
Because we can't really sure about the credibility of the information.
Step-by-step explanation:
In online news era, everyone can write 'news' with some basic knowledge in blogging and search engine optimization. As long as they can bring their piece up high in search engine results, many people will believe that the news is coming from someone with credibility's.
This is why, it is extremely important for us to fact-check every information we read online.
One way to do it is by checking the news from different news-source. If there vast majority of credible news-sources confirm the content of the news, than we can be sure that the news is factual.