True, but at least it's not single use. Is there a viable alternative? A non-petrochemical plastic that has the same qualities? It's not like they can whittle them out of wood or cast them with metal so it'll always be some form of polymer, and I'm sure they would jump at a more ecologically sound option.
lego compatible bricks made from wood do exist. they probably don't last as long though.
Lego has been testing making some pieces out of corn-based plastic or other natural plastics. https://www.lego.com/en-us/sustainability/sustainable-materi...
Some of the first forays resulted in notably lower-quality bricks.