Nakedness is a problem when women (including rape survivors), children, religious women, refugees, etc etc etc are passing by and are being flashed. Next you will say 'what is wrong with men in trenchcoats flashing children?'. Because that is basically what this is. There is nothing 'fun' about this if you are an unsuspecting child or trauma survivor who sees this.
And yes, there are men with erections and children passing metres from these men, see my link above.