There is a variant of the chair that have gaps in the seat to prevent rain from pooling. While it's a useful feature, it also presents a danger because sitting on them can cause the gaps to widen, allowing things like testicles to pass through, and get caught when the person stands up.
Yeah I’d say the ones with drainage is just a variant.
And there are different types. That commenter is probably referring to the kinds which have very long narrow slits in the seat. Which could probably catch your balls if the plastic got stretched or warped.
At a shop I used to work at, we had these old computer chairs with hard plastic seats. The plastic would flex and crack just forward of where the metal seat pan was, so when you sat down you'd inevitably apply a load to the front edge and open this crack up.
We joked these were Trump brand chairs given their tendency to grab ya by the pussy.
In some parts of the world they probably provide seating for like 99% of the population. Like every picture I’ve seen of west Africa with a cafe or a gathering, it’s always these chairs everywhere.
These chairs remind me of an over weight relative who was visiting in Arizona, where a friend had a covered back deck with these chairs. Our relative sat in one, not aware that the heat melts those things even when shaded. She flipped over backwards into the flower bed behind her, fortunately the deck was only about foot off the ground so she wasn’t hurt. It was very funny to watch though.
Wheelie bins are probably made in the same way, only with a differently shaped mould. There are probably other common objects that also belong to this class.
Lots of things could be “monobloc”. Cutlery, flower pots, plastic army men, etc.
But a wheeliebin definitely is not one. There’s at least 4 parts to a wheelie bin. Body, lid, 2x wheels. Probably closer to 8, as you probably have 2x clips for the lid, an axle, and some form of axle retainer. Even more if you count the individual parts of the wheel and bearings.