My personal 2 cents (not Hospitaller's stance however) is that a mercenary may be loyal to the coin, but their past actions still speak volumes about them. If you're a sell sword for one faction and attack "us", then you're an enemy, regardless if you were paid to attack or chose to do so willingly. The reason's behind your motivations don't matter to me, only the fact you fought against us (with resources, not just signing up against in battles).