Consider the world as it actually is. There are three possibilities:

(a) God is more likely all evil than all good
(b) God is less likely all evil than all good
(c) God is equally likely to be all evil as all good

If (a), then it is unlikely that God is all good.
Not (b), since "the belief that God is all evil can be justified to precisely the same extent as the belief that God is all good."
Therefore, (c).
"[I]f (c) is correct … then [the facts of the actual world] do not support the excuses which could be made for a good God permitting evil."
Therefore, there is no acceptable excuse for God permitting evil.