People call it a religion now ... because there isn't a state anymore (called a caliphate). Which illustrates yet again how central the state is to islam. All states, including the Taliban and the Mullahs of Iran, radically de-emphasize the fact that the islamic religion demands a global central totalitarian state, and emphasizes nationalism and, for example, the difference between Iranians and Pakistani. Every 6 year old Iranian knows how "their islam", first, centers around the Iranian state, and second how pakistani islam is totally wrong. Plus, of course, how trying to work out those differences, as the "one islam" ideal in the religion itself would seem to reward, is treason.
The Inquisition didn't have any problems with Galileo and his theories until he started insulting the pope in one of his books. Then the theories became a pretext to pressure him.