Why is the Fermi Paradox a "paradox"?

The Fermi Paradox is based on the assumption that the universe is full of life. What exactly is this idea based on? How can you measure how likely or unlikely it is for life to come about on its own in a certain part of the universe? How do you know that is even possible to begin with?

It's a complete joke. It's based on something that some people pulled out of their wild imagination, not something that could be objectively measured and experimented with. In science fiction the universe is full of life but that's why it's called "fiction."

I had to let this out because the Fermi Paradox is one of my pet peeves.