If you take a bath and come out clean, why does your towel get dirty?

its because its taking all the dry skin off your body

When you say that you wash away bacteria during washing, you are partially right: yes, some germs are destroyed. But others will remain, and they will fall on your towel while you wipe off after a shower ... Soap and water clean dirt, sweat and some of the bacteria off your body, but not all of it.