I think there's a risk as adults that we underplay the impact of 'pervy guys getting their dicks out in public'. As a girl, both pre-teen and teen I was very disturbed by the number of times I was (literally) exposed to it, just as I was branching out independently - on Hampstead Heath, my local park, on my own in a subway, in the National Gallery, the tube and Paris metro. I became very fearful of men and worried about rape.
I would cope differently now of course but am no longer targeted as I'm no longer young and vulnerable. I had to be reassured by my sister that 'flashers' are not rapists - though I'm not sure the science is as certain as that. Terms like exhibitionism diminish the impact - it is threatening and makes girls feel unsafe and at risk.
The naivety of Jess B and others to imagine their 'thing', their jokey fetish is acceptable shows how little they understand what it is to grow up a young woman. I applaud anyone who stands up to it. It impinges on women's freedom to travel safely and confidently through our streets and society. It's not a narcissistic right - it's a threat.