Einstein didn't nab Eddington and ask him to
observe starlight passing close to the sun on his expedition to help form or even prove his theory.
He wrote, "If the redshift of spectral lines due to the gravitational potential should not exist, then the general theory of relativity will be untenable."
I.e. It was the first opportunity to try and falsify his completed theory.
In addition, since then, that predicted "redshift" has been observed many times. (just one thing the theory predicts).
What a stupid thread by the usual stupid people.