I agree with you, but I think you should be clear in your words as well as in your head that it has everything to do with the individual dog's behavior and nothing to do with the breed (which actually tends to be safer around humans than many other breeds, but can be animal aggressive). Making it about "pit bulls" is just going to cause people to dig in their heels.

Any dog can be territorial. No dog should be allowed to display territorial behavior in an office setting. Period. The dog needs to know that the space doesn't belong to her/him.