Do you know what a fact is? That's easy. Of course you do. Fact is an objective truth not subject to interpretation or dispute. Water is liquid if it's above 32 degrees Fahrenheit. That's a fact. Thursday comes after Wednesday. That's a fact. The address of the White House is 1600 Pennsylvania Avenue.
People who deal in actual facts can recognize that an assertion is either fact-based or its not. It's really not that complicated. That's for normal people who understand what a fact is. But there are other kinds of people, those who don't know what a fact is because they are apparently not intelligent enough to understand such a straightforward concept. Ironically, and tragically, many of these people have found work doing something that calls itself - but patently is not - "fact checking."