Milan says that Galileo did not have proof of the heliocentric theory. I think he did. Did any serious scientist, after the publication of Galileo's Dialogue, defend the geocentric idea on scientific grounds? I know of none. Grant that this was due as much to Kepler's work as Galileo's; still the point stands.
But there is a more fundamental point. What possessed the the Church to declare solemnly that physics is a matter of faith, to command that its flock should disbelieve the evidence of their eyes and their minds?
Tycho Brhae. His model, in which the sun orbits the earth, but the rest of the planets orbit the sun, was just as consistent with Galileo's observations as was the Copernican model. It took the discovery of Newton's laws of motion and graviation to thoroughly disprove geocentrism.
Yes, the reference to Kepler is misleading, also because it omits the fact that his book was placed on the index in 1616.
In any case the Church couldn't threaten Kepler with excommunication, because he wasn't a Catholic in the first place; and if the Inquisition had tried to get hold of him in person, it would probably have failed.
Well, Kepler wasn't Catholic, that's true, but he did do a lot of his work while living in Catholic territories (prior to 1616). So if the Church really was dogmatically attached to geocentrism (it wasn't), then it certainly could have gotten its hands on him.