Why, in principle, would it not be possible for us to design an AGI, that would have care for our (all sentient beings') welfare or care for the investors' profit as (one of) its core goal(s)?
To make a biological comparison, the vast majority of humans have a deep, intrinsic need to procreate and have children. It doesn't really follow from some rational analysis — it's just there, presumably "imbued" into us by evolution, as humans who didn't have this need had fewer (or no) children. Similarly, why could we not design an AGI that has a need (or a suitably chosed reward function) to fulfil some chosen goal?
Whether doing that would be moral (IMO it could, depending on the details) and whether we wouldn't mess up the design, subtly or otherwise (conditional on AGI actually being developed, I'm frankly pretty terrified), are two different questions.