I suspect one of the causes of this is that it's so incredibly easy now to find articles in the Internet that support your viewpoints that can then be shared ra

I suspect one of the causes of this is that it's so incredibly easy now to find articles in the Internet that support your viewpoints that can then be shared rapidly amongst your filter bubble. It used to be the case that there was a non negligible barrier to get an idea published and in front of the eyes of millions of people. You had to find a publisher, pay for publication, and then convince stores to carry a book/magazine/whatever. With the Internet, you can put up a blog post and share it on Facebook with a budget of $0 (or bus fare to the library). It's just as simple to find websites that support a view of the moon landing not happening as it is to find websites that do. Both are just a Google search away.