Do you think that people should be required to view websites as delivered, without modifying them in any way? That would be the logical end of attempting to prevent this kind of "stealing".
If there is another term you'd like to use for "looks like theft, but the original owner loses nothing" then feel free. But it is not theft or stealing, those require also depriving the rightful owner of the stolen property.
If I could duplicate the exact contents of your car, would it still be "stealing" if I did so? Reminder that you would continue to be in possession of 100% of the contents of your car. Maybe with regards to any digital data on any duplicated devices, I could see a bit of the "stealing" logic, then again nothing was actually "stolen" from you if you still have 100% of your original property, but I now also have duplicates of that property.