True but those are official opinion. Even Zenith of Imperial truth Emperor is forced to admit that despite paying lipservice to Imperial Truth Many of Imperial worshipping him secretly in their home. He is being constantly bombarded with their Prayers. He can not just kill them because skilled personnel are so hard to find so he gritted his teeth and forced to endured that and planned to deal with after Crusade. We all know how that ended. Now Imperials have greater proof of his Godhood. No matter what Emperor says they will not just accept that. Thry may think this is a test or pay lipservice to Imperial truth. But it will certainly create greater number of hidden worshippers.
Let me put it this way. Where does it say, "The Emperor is a god?" Where does it say, "They worship the Emperor?". They believe in him and it talks about them having Faith in the Emperor. Keep in mind that most SMs view the Emperor, even in 40K as their Spiritual Liege.
Where did you get the idea that the Emperor can "Hear Prayers"? Besides which, True Faith explicitly does not send out Prayers, regardless if the deity you worship is real. It is purely internal, so even IF they worshiped the Emperor, and IF he was able to hear prayers, he would not be bombarded by it from the Heralds because True Faith is internal.
Second, I reiterate, that they are using traits of True Faith and not deriving any power from the Emperor. In the last interlude, I hinted at this, and they were deployed only after Extensive testing.
Meaning both the Marines AND the Emperor had tested fully, what True Faith is before they were deployed against the Cults and daemons. So they know quite well, that the Emperor is not "Granting" them power.
Finally, I again reiterate. The above is a Propaganda piece from very early in the Crusade meant not for the General Public but the Soldiers and Politicians, where the Emperor still has not quite nailed down just WHAT true faith is, just that it helps greatly against Chaos and is internal as opposed to external.
I will not say more on this as I have hinted enough on what he is trying to achieve here.