[widowithfoursons]

Then why isn't it called the "fact" of evolution?

[Dan Day]

Then why isn't it called the "fact" of evolution?

Clearly, you didn't bother reading the links I provided you, since one of them specifically addresses your question.

Try again.

Meanwhile, I will ponder the adage about leading a horse to water.

[Doctor Stochastic]

For the same reason we talk about the "Newton's Theory of Gravity" or "Einstein's Theory of Relativity" or "Group Theory" or "The Theory of Equations" or "The Kinetic Theory of Gasses" or "Number Theory."

A theory is an explanation (coherent, one hopes) of a set of observations.