Its more like standing outside a restaurant with a live band and listening to the music without going in and paying for dinner. For me, what indicates that this charge is totally wrong, is the fact that the supposed “victim” didn’t have a problem with it. I could maybe understand if the victim was concerned or upset by the action.
If people steal bandwith from ISP providers the theft is costing the ISP customers and/or owners. The use of the service is not cost free.