>>13793755if ghost types and rock types can be hit with poison steel types should be hit by poison, neither are typically "biotic," although MOST steel, rock and ghost pokemon look pretty normal and poisonable to me, such as lucario, rampardos, or banette.
bronzong gigalith and yamask don't look "poisonable," the fact that only steel is immune is just an extra unnecessary kick in the nuts to poison.
nobody can argue that it's reasonable that a snake made of rock can be poisoned but a snake made of steel can't.