[T]here’s nothing I prefer/antiprefer exist, but merely things that I prefer/antiprefer to be aware of.
is a conceivable extrapolation from a starting point where you antiprefer something’s existence (in the extreme, with MWI you may not have much say what does/doesn’t exist, just how much of it in which branches).
It’s also possible that you hold both preferences (prefer X not exist, prefer not to be aware of X) and the existence preference gets dropped for being incompatible with other values held by other people while the awareness preference does not.
It’s a potential outcome, I suppose, in that
is a conceivable extrapolation from a starting point where you antiprefer something’s existence (in the extreme, with MWI you may not have much say what does/doesn’t exist, just how much of it in which branches).
It’s also possible that you hold both preferences (prefer X not exist, prefer not to be aware of X) and the existence preference gets dropped for being incompatible with other values held by other people while the awareness preference does not.