If i take your line of thought and apply it to the wallet thief, a mugging can have serious phycological and physical effects on their victims. As with all crimes, you could make the argument that unless the wallet thief is stopped there an then, it might be the start of a deteriorating pattern of behaviour that ultimately leads to assault, knife crime or murder.
Taking an argument to the extreme to try and make a point just makes the discussion a waste of time.
In isolation, flashing is distressing and is not acceptable, but when resources are stretched as were in this context its not going to be prioritised in exactly the same way that other petty crimes will not be prioritised at that exact moment in time.