The link in the OP was to Toronto. I've also seen similar posted from New York and Seattle. Here, we've seen the (clothed) pup thing but with strong associations of "kink" ie something you don't do in public.
There is no other community event that is associated with public nudity or adult sexual activity. Here, exposing children to adult sexuality is abuse:
"Involves forcing or enticing a child or young person to take part in sexual activities, not necessarily involving a high level of violence, whether or not the child is aware of what is happening. The activities may involve physical contact, including assault by penetration (for example, rape or oral sex) or non-penetrative acts such as masturbation, kissing, rubbing and touching outside of clothing. They may also include non-contact activities, such as involving children in looking at, or in the production of, sexual images, watching sexual activities, encouraging children to behave in sexually inappropriate ways, or grooming a child in preparation for abuse. Sexual abuse can take place online, and technology can be used to facilitate offline abuse. Sexual abuse is not solely perpetrated by adult males. Women can also commit acts of sexual abuse, as can other children."
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachmentdata/file/942454/Workinggtogethertoosafeguardchildrenninteragencyyguidance.pdf
I would hazard a guess that Canada and the States have definitions like that as well.
I agree with PP that one day we will look back and shake our heads.