Because it is important to preach the Christian Gospel in truth.
And anti-Scriptural hallucinations and ignorant swindles are not the Gospel of Jesus Christ. That is not Christianity. It’s superstition and “vain jangling.”
It must be noted that the story concerning The Miracle of Guadalupe is not without controversy even in the Catholic Church.
The following links serve to illustrate some reasons for scepticism. (I will not attempt to make a case for objectivity just as proponents of the authenticity of the story make no attempt to claim objectivity.)
Boston Globe article which touches on the subject.
Sceptic site - definitely not objective.
Something to think about. Scroll up and down for more complete information.">