It’s not about whether it’s overtly sexual. It’s about normalising men swinging their penises in a public street.
That is a gateway to groomers being able to say nakedness is ok.
And then it’s harder for kids to say “this is not fine”.
So if some Uncle Bob sends your 13 yo dd a photo of himself and his mates all starkers, getting ready for their naked bike ride - is that now? He is just letting her know he’s protesting climate change at a protest and happens to be naked. She laughs, it’s amusing and uncle Bob is nice.
And next week some random bloke sends your dd a dick pick - is that now also fine? No. But it’s now a grey area because sometimes it’s fine and valid for an adult man to be naked
If we are allowing naked bike rides, anything could be done naked surely?