It's true that leopard frogs are difficult to make calm around people. Probably impossible to. Although, If they have lots of cover, then they will be much less stressed than in an open space. It truly is just natural for them to take to water/cover from anything that comes by. Even a mouse would startle them.

"In contrast, the toads I raised would take food from my fingers, but were an absolute PAIN to find tiny crickets for."

^^ 100% agreement with this statement. Not that it's related to leopard frogs, but my toadlets will actually sit directly on my hand and eat a mealworm, also on my hand, in front of them.