Is this your first experience/exposure to the us legal system?
Defending yourself from an accusation using a hypothetical admission doesn't actually admit to it. e.g. I didn't murder anyone, and I didn't steal that car, but if even if I did murder them, and steal their car, the car's expired tags wouldn't apply to me because [reason].
If you care about justice, you want to enable every truth to come out, and be decided on. If you prohibit someone from making an argument, because it might imply something that is separate, you limit the the possible outcomes to something strictly less fair. If someone did murder a person them and took their car, they should be prosecuted for that, but just because you did commit crime a, and crime b, doesn't mean you should be convicted of crime c. Even if crime c is the least significant. That's still not just.
Defending yourself from an accusation using a hypothetical admission doesn't actually admit to it. e.g. I didn't murder anyone, and I didn't steal that car, but if even if I did murder them, and steal their car, the car's expired tags wouldn't apply to me because [reason].
If you care about justice, you want to enable every truth to come out, and be decided on. If you prohibit someone from making an argument, because it might imply something that is separate, you limit the the possible outcomes to something strictly less fair. If someone did murder a person them and took their car, they should be prosecuted for that, but just because you did commit crime a, and crime b, doesn't mean you should be convicted of crime c. Even if crime c is the least significant. That's still not just.