Death: what I was going for.

Maddox: Generally speaking we try and keep away from other races, but we're often sought out. Humans found a way to bind us a long time ago, and by accident, but it's known now, so the less were around during others the better. Newbies don't have to worry about the binding thing thougj, not until after they have learned to access other realms. 

Death: that and we're often misunderstood. Yes reapers ferry souls, but they cannot take or give life. I'm special and can. Reapers are often sought simply because we can access all realms, no questions asked, no prerequisites. That and we can come in direct contact with souls. 

Clary: and binding Reapers passes Death off because he feels like it's a low blow. 

Maddox: it also doesn't help because it is assumed our neutrality is choice, but it's not. We must remain neutral.