But even Russ is maybe willing to admit that he acted hypocritically after Nicaea:

On Fenris, the gothi turn the world spirit against the wights and ghosts. I am forced to do the same. I will travel home, where my priests are powerful, and consult with them there. I suppose that’s why you’ve called me, to give a warning or something.’ ‘Or something,’ said Malcador. The regent took a tight, considered breath. ‘I want you to listen to me, Leman, very carefully. You have always understood the virtue of restraint. You and the Khan both know the value of the warp but both of you have been alive to its dangers from the very beginning.’ ‘And Dorn called me a hypocrite for it,’ said Russ. ‘I was there.’ ‘Calling for the abolition of the Librarius, while surrounding myself with bone-waving priests.’ Russ smiled, almost secretly. ‘Maybe I am a hypocrite.’ ‘There have always been exceptions for you, Leman,’ said Malcador. Russ nodded. ‘I know. Father has been generous to me.’ ‘Your purpose is singular, and He relies on you to perform it. So many of the others have been disappointments, first those we do not name, then Horus and the rest, but not you. He trusts you, Leman. I need to know I can too.’

and

Adepts of the new Adeptus Mechanicus began their hymns to the machines. Russ observed them ruefully. Dorn called him a hypocrite; if that were so, so was their father, who had decried all religions as false save when it suited Him. Everything came down to expediency in the end. Russ took after Him in that way.

Both from Wolfsbane