system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40K] Why aren't the Space Marines more vocal about the outright lies of the Ecclesiarchy?

The Emperor loathed all religion, and insisted on spreading the teachings of skepticism, science, and reason throughout the Imperium of Man.

Though for most this truth has been lost to time and the efforts of religious zealots, almost all of the Space Marines hold to the Imperial Truth.

The Space Marines know that the Ecclesiarchy are pushing lies that go against the Emperor's will. Why don't they make a fuss about it?
gpt
Many chapters have faith in the emperor that exceeds that of mortal men.

The founding chapters would be aware of the Emperors Opinion on the matter. However, that was before the time of chaos gods tearing into the Imperium. Erebus was proof that men need faith, and faith in the Emperor is the best defense against Chaos.