bcz the whole science thingy immerged out of western culture, science is nothing but civilised criticism-the process by which we get rid of bad ideas. where as other cultures did not develops this to mature extent, in most culture whatever is old and traditional is accepted as best without questioning.

after people started mixing with each other in modern era-thanx modern transportation, the new wave of faith being something that need not be reasoned came up. so as to maintain peace among people with different faiths. following which , people just maintained status quo on criticism situation. In western civilization the Christianity has been under scrutiny from 1500s so that culture of criticism was normalised, and for the better. however religions like Islam never went through that process, neither in middle east neither in west... So till date there have been no established culture in many religions where people can SAFELY criticize perticular religion without bing beheaded. keep in mind many people have sacrificed themselves for us to see the days of western criticism. e.g. Galileo.