Because it can/will be used by certain groups of privileged classes to perpetuate said privilege, up to and including things that could cast shadows similar to

Because it can/will be used by certain groups of privileged classes to perpetuate said privilege, up to and including things that could cast shadows similar to eugenics. It's where the edges are that matter here, not just the basic idea. And when people say "that just couldn't happen" given the last half decade of societal weirdness, is no longer a really acceptable response anymore for many.