Galileo was punished by the Church for teaching that the sun is stationary and the earth moves around it. His opponents held the view that the earth is stationary and the sun moves around it. If the absolute motion has no meaning, are the two viewpoints not equally correct or equally wrong?
Consider a bus is travelling on a road and we are seating at the window seat in the bus. With respect to the bus (frame of reference), we are at rest. But, we are moving (along with the bus) with respect to the road (frame of reference). Thus the viewpoint is important to conclude if something is at rest or moving. This is called as frame of reference.
Opponents of Galileo were taking our Earth as frame of reference and concluded that the Sun is moving around earth. If we consider the frame of reference as Sun, then we say that Earth is moving around the Sun. Galileo might kept himself on the Sun or at a point in the universe and then analyzed this situation in his brain. If suppose we consider a point in the universe as frame of reference and look at the solar system, then it is correctly found out that the Earth is moving around the Sun.