Asimov himself wrote a short story proving how even in the scenario where the three laws are followed, harm to humans can still easily be achieved.

I vaguely recall it involved two or three robots who were unaware of what the previous robots had done. First, a person asks one robot to purchase a poison, then asks another to dissolve this powder into a drink, then another serves that drink to the victim. I read the story decades ago, but the very rough idea stands.