Defending yourself or others, no matter how evil they are, should never result in a reputation loss. Only evil actions should be punished this way.
You align yourself with Valen, when you accept her as part of your group. So only taking her into your group should result in reputation loss - as it is with Viconia.
When you have Valen in your group and act neutral, there is no reason for hunting her down, only because she is a vampire, which is really racist. Defending her in this case should be considered righteous.
When you act evil, you already lose reputation through the evil acts themselves. Which only then would justify the appearing of hunters. But this is already handled by the game, because you'll get attacked by paladins and mages, if your reputation is too low.
The reputation loss of this mod, because you defend Valen, is absolutely illogical.
We are not the aggressors.
Peace out.