Um, actually. They are not kidnapping you. By law, they are detaining you for suspicion or commitment of a crime. It is not kidnapping, it is detainment by law.
well i can understand your point but kidnappings meaning is "the action of abducting someone and holding them captive" the meaning of arrest is "seize (someone) by legal authority and take into custody"
but being arrested is also 'holding them captive'
because the person is put in handcuffs, and put into a back of a police cruiser
basically keeping them in one spot, and putting limitations on their movements