That's the whole point of science!
Making new discoveries and improving our understanding of the world is how it works and is science's greatest strength. Nothing is science is sacred, nothing is dogma - everything can be challenged if you have the evidence.
I really don't understand why people have a problem with this. If you want to go back to a medieval way of life, be my guest.
Also, nothing is ever 'absolutely true' in science. Every theory can be changed and adjusted as new discoveries are made and new evidence comes to light. Science wouldn't work if it just held onto ancient dogmatic ideas and claimed they were absolute truth despite what discoveries about reality might say - that's religion.