My family plays horseshoes. 16 oz metal ‘U’ shapes being tossed through the air while drinking beer. One could argue that the problem with lawn darts was that they were too light, allowing children without proper sense to throw them too far.
I don't think children should be going anywhere near such things without adult supervision, but completely banning sale seems like a wildly disproportionate response.
But throwing a dart high in the air and hitting a wandering 2 year old actually did happen, and there was no real attempt to only their the darts in one direction