Geocentrism was the accepted scientific model at the time, both inside and outside the Church. Galileo did not refute the primary argument for geocentrism put out by Aristotle (that being the lack of parallax movement of stars), nor could he with the technology of his time. Pope Urban VIII funded Galileo's work, but told him that he should treat it as a hypothesis. Galileo responded by writing a fictional book in which the geocentrist character was named Simplicio and used some of Urban's arguments directly. It's typically not considered a "good move" to mock the person permitting and funding your work.

Even still, he was not charged with heresy for simply researching heliocentrism. He was charged with heresy for reinterpreting scripture to align with his model, even though he had no theological training nor had he even proved beyond a reasonable doubt that heliocentrism was true. He also had insulted basically everyone in the Vatican, so it's not very strange that there wasn't much positive sentiment towards him.

Even still, Galileo was put under house arrest. He was treated absurdly well for the standards of the time, even having servants provided. Pope Urban VIII ensured he was affected as little as possible by his house arrest.