It is absolutely ridiculous to compare this situation to the one you are reporting. One is of a group of people unarmed and not a threat stood in a corner compliant and being gunned down regardless, and one is a raid with multiple visibly armed people who are high threats in the situation. It has always been allowed as far as I'm concerned to shoot people in a raid who have weapons on their back unless they are clearly not a threat (for example, afk in a corner or completely unaware of what's going on and unaware of their intentions).
It is stupid and absolutely ridiculous to even attempt to compare these two scenarios in any way, shape or form. however in no way am I making a judgement on whether or not this was a breach of the rules or not, I'll leave that up to the staff member who deals with this AR.