In a more progressive world, we might do the opposite -- "pro-sex" beds for adults that are healthy, in great shape and have made good life choices to get to the Olympics. Many countries are realizing a potentially declining birth rate. Maybe we should encourage well adjusted young people to be hooking up.
More seriously it is a fucking bucket of crabs out there. "If I'm not having a good time you can't either!" is a growing attitude of idiots.
None of the athletes are going there looking to conceive. The countries are probably thinking they invested in the training and their athletes will screw it up (literally) by focusing on alternative activities.
Well trained people like this can do it in positions that don't put the full weight on those beds. Might even call it part of the training. Or just put the mattress or stack a couple of blankets on the floor. The size of the beds looks similar to dorm room beds, another place famously failing to keep people apart.
I really think they went for cardboard more for the sustainability (and costs) angle but "anti-sex" gets the clicks.
You certainly won't be winning a gold medal in conception with that attitude. At least you wouldn't in the progressive society that hosts said Olympic sport.
Either way, everyone knows these "anti-sex" beds wont actually stop sexual activities. If anything, this will encourage them out of rebellion.
Why wouldn't "unintended pregnancies" help "grow a healthy population."
From what I've read, a major factor in the declining birthrate is perfectionism (e.g. people thinking they can't have a kid unless I have X, Y, and Z (usually expensive) things just right, when in fact the kid will turn out fine without those things).