Lets see how you have worded it.
So what I am getting from this is, we killed something and it is a big deal, it was easy for us and the Counsel clearly needs help, so lets help them out.
This is not how we plead for our lives. Because that is what we are supposed to do. The context is that we are trying to convince Ebeneezer McCoy that we are not a warlock or a dark magic addict.
The fact that we killed the outsider and had Uriel vouch for us is a +. But that statement right now comes off as arrogant and gives the impression that we are high on our own power. Which is NOT what we want to do for the "Do not loose your head" reason.
Offering help at least puts us in a similar position as a Knight of the Cross like Molly's father, even if we are using Nuclear hate fire and hell themed energy.
But we really, REALLY do not want more comparisons to warlocks and other people drunk on their power then absolutely necessary. THAT is not how we plead for our lives.