{SPOILERS} I got an iconoclast ending but why did Imperium see me as a threat after all I have done?

I rejected Chaos powers, stopped Calcazar's plan and helped Nomos ascend to protect Coronus Expanse.

And then for some reason, Imperium branded me as a heretic. What was their reasoning though? Is it because of ban on AI technologies? The presence of Nomos was well known to Adeptus Mechanicus though.

I understand that it is explained implicitly ( Golden Throne became afraid of competition) but I would like to confirm my interpretation. I also helped Amarnat form the schism, so maybe it added fuel to the fire.

Nomos himself though does not contradict the cult of God-Emperor, does not kill or hurt anyone except Necrons. Neither does he have explicit ambitions outside of Koronus Expanse. The cult of Emperor exists freely in Koronus, Sister Argenta even founds an order and>! "whacks Lord Inquisitor Heinrix"!<
Basically, you have a Ctan-like God who is super friendly to humans, hates Necrons and Chaos , why would anyone be mean to him? Especially, after Rogue Trader destroyed Cult of the Final Dawn and Drukhari Cabal.

After all, as Xavier said, the main threat to Imperium is Chaos, not Xenos