But it is a perfectly correct frame of reference and much better than all others I can think of. Where else is there proven intelligent life?
What do you mean by that? I'm familiar with the term "inertial reference frame"; it has a specific meaning in Newtonian mechanics and an equivalent meaning in both special and general relativity.
Where else is there proven intelligent life?
What is the relevance of proven intelligent life to defining a frame of reference for the universe?