My opinion is based on reduction arguments. Children, mentally incapable, criminal etc. cause huge exception gaps. As technology gets increasingly close (be it cloning/genetics or AI) to replicating intelligence, we also are attacking our pre-conceptions around consciousness and what it means to be human. Every argument I have heard that requires the presumption of humans as being different ends up with those exception gaps.
I also find myself definition chasing. Does an eye-seeing dog have responsibilities? Can they be held responsible? An eye-seeing dog that fails is likely put down; is it significantly different than our criminal system? Same outcome, but different process.. Yet we don't hold all humans responsible (insane, incapable, immature). And if mental faculty was the determinant, is it just a hurdle? Are we really proxying the loss of rights when someone acts (arbitrarily defined) irresponsible? That negates the entire concept of rights.
Even the concept of responsibility is not entirely factual. It's no longer a good argument to say that we have "someone driving us" that is responsible. We don't. It's not clear where the animal ends and human starts, if there is even an objective line.
The only way I know of to resolve these differences is to claim rights aren't given to individuals but to groups, and in that way, we can take away individual's rights so long as it maintains the group's. Every exception then proves the rule - we take away rights from those incapable, proving that a being that is capable has rights. We don't give children rights because they aren't yet capable, proving that they will (as a group) eventually become capable. We give certain animals "responsibilities" (even if they could not held responsible) by exception, proving by exception that they are not responsible.