Anyone who believes that Muslim conquerors did not impose Islam on the new subjects is either denying history or unfamiliar with it. The choice was recognize the new religion or die. That was the fashion back then.
What would happen if the field trip had been to a Baptist church, with the same emphasis on quotes, explanations etc.?
I have no problem with such field trips. I recall going to synagogues and other non-Christian facilities in my long ago youth without ill effect, and actually quite interesting.