Why when you change a motorcycles air filter and exhaust you need to re-jet the carb and on a car you don't?

Even if the motorcycle is fuel injected they recommend you re-jetting; but, for a car or truck or something like that you don't have to do this?
Why when you change a motorcycles air filter and exhaust you need to re-jet the carb and on a car you don't?
The motorcycle does not have an ECU that works it's maps out for it. A motorcycle needs to be mechanically induced to accept more fuel by being re-jetted and not through any sort of an electronic process. In a car you can remap the ECU to deliver more fuel but in most cases an exhaust and intake for a car do not throw it off as much and this is not needed; though more power can be gained by mapping correctly. Motorcycles will gain a lot from an unrestricted exhaust and will most likely lean out without a proper jet change.
Why when you change a motorcycles air filter and exhaust you need to re-jet the carb and on a car you don't?
Carbs have jets fuel injected does not.