Again this where I think the scale of the consequences is not being considered, because we simply aren't used to it.
We normally debate morality and principal and weigh them against much smaller consequences, loss of property or privilege. And in some cases the loss of a single life, or the life of a specific group.
But when you are talking the annihilation of your world, perhaps your entire species (hell in the Orville's case the annihilation of hundreds of worlds and species)..... "isn't convenient" doesn't even scratch the surface, and its disingenuous to think that the standard of a principal has to hold out against any and all possible consequences to be considered a principal.
If I might use a scientific approach for a moment. In my engineering training, we were taught that superheated Steam is water that is heated above the boiling point, often many hundreds of degrees hotter. And for all common cases of engineering, this definition is perfectly useful and correct, with common properties exhibited across many hundreds of degrees of temperature. However, when dealing with temperatures approaching that of a star for example, well now you are entering entirely new phases of matter (plasma being the most common). The definition and properties of superheated steam really does not hold anymore, its a brand new ballgame.
The point being that the case of "utter annihilation" is a consequence so far above the standard that it requires a whole new approach and consideration. A principal that stands up against all lesser consequences is one thing, but then to state it must stand up against this ultimate consequence to be valid.... that to me is no longer morality but insanity.