Because you can't answer it.
A church is defined by its beliefs. If someone claiming to be a member of a church publicly repudiates or distorts a teaching of his church, his church has a right to punish or excommunicate him.
Galileo's punishment may have been unjust and imprudent, but Church tribunals are not unjust per se.
It's interesting to note the part of my original post you didn't see.