I just did.
You want to know how we know. Metaphysics.
Before you examine the data, you decide on a degree of confidence that will convince you.
You collect your data, or plot data that was independently collected. You write an equation based on a theory. You draw a line through the data based on that equation. It matches. The conclusion: the theory that draws the line explains the data.
You check that level of agreement using statistics. It matches to that level of confidence.
You write a paper. You present it. You get questions from your peers. You answer them, or you identify where additional work is needed, either to the theory, or to the data.
All fine, all generally anecdotal. Where there may be some mathematical modelling concerning populations, it does not address the specific question of how you know evolution is not a uniform process? So far all you've answered is why one might think it is not uniform.
If you can't answer simple direct questions you ought not get all huffy, coyoteman. Science isn't telling stories. My mind is made up about that, yes.