Even if I could create sentient beings, this wouldn't imply the power to declare what is good or true by fiat. 2 + 2 = 4, massive objects attract each other gravitationally, and it's morally problematic to put children in ovens for being Jewish even if a maximally powerful alien or wizard said otherwise. These things cannot be changed by any fiat, and being very powerful doesn't make it any more possible.
> this wouldn't imply the power to declare what is good or true by fiat
There are volumes upon volumes of philosophical work spent discussing this one idea. I wouldn't think less of someone simply for having a different point of view, especially if it might be supported by more than a back-of-the-envelope argument.