Because it is a good story. Just because they may agree with the choice in it doesn't make it propaganda. I fail to see how saying it is the right choice in some cases makes it propaganda. That I thought was true long before I ever saw the movie. There are many other movies I would rather ask why Hollywood made than this one. Son of the Mask, I'm looking at you.
Just because you don't need convincing, doesn't mean that the purpose of the movie isn't to convince. There's a difference between art designed to make you think about an issue and propaganda designed to sway public opinion. Does the line between the two get blurry? Damn right! I don't think it was blurry in this case. The other view was represented by an effeminate, foul mouthed, platitude spouting ineffective priest.