Because if we were at the center of a rotating cosmos, it's a logical conclusion, that we would not be moving anywhere. Actually, what I wanted to say is that this is our starting point. Our starting observation. That we are not moving, and that everything else is moving around us. This starting idea can be wrong, but we need evidence for that first.
If it's as self-evident as you seem to think it is, why have virtually all scientists come to the opposite conclusion?
Ridicule is the only weapon which can be used against unintelligible propositions. Ideas must be distinct before reason can act upon them; and no man ever had a distinct idea of the trinity. It is the mere Abracadabra of the mountebanks calling themselves the priests of Jesus. -- Thomas Jefferson
For we know that our patchwork heritage is a strength, not a weakness. We are a nation of Christians and Muslims, Jews and Hindus -- and non-believers. -- Barack Obama
We see monsters where science shows us windmills. -- Phat