This is a mod for Napoleonic Wars. As such, you should understand that when you try to use the name of a reputable regiment in this community, there could be a disagreement.
The fact is the 84e already existed before you decided to reserve it for this mod, and now you've been asked not to use it. If you had any respect at all for the larger NW community as a whole, I would ask that you revoke or change your reservation.
Doesn't anyone else see why there is this public reaction? What if it was your regiment that someone was trying to impersonate.