Heresy. You keep using that word. I do not think it means what you think it means.
And whilst offering due obeisance to your command of the militia, nor do I believe you are qualified to make the claim. Heresy is decided by the Theology Council, and I have not seen evidence of your membership of that august body.
Political and strategic differences of opinion are not, of themselves, heretical. This seems to be a disagreement of a temporal nature, not a spiritual one.
It seems to this poor soldier that publicly encouraging division amongst the servants of Holy Amarr is counterproductive at this perilous time. A private petition to the relevant Authority would be the wiser action. I admit to some bemusement at the actions of LUMEN, but as neither Lord Sarum nor the Empress has made a statement on the matter, I may assume, as some here have argued, that they are doing the Imperial Will.