possibilities exist.

a] they may be exhibitionists

b] they dont realise they are misconfigured

c] someone hacked them to whatever end

d] they are doing nothing wrong thus believe they have nothing to hide.

Or they don't even know the camera is there. I've heard of landlords doing that in tenant's private spaces, including bathrooms. When caught, they like to claim they are just keeping an eye on the property, but everyone knows they are just perverts.