Rowe-style arguments from evil contend that there are evils that are inscrutable in the sense that we do not know a justification for them.
Let's say a justification for E is a reason R such that, in light of R, God would be justified in allowing E.
An evil is inscrutable provided we don't know a justification for E. But what does it mean not to know a justification? On the strongest reading, there is the ability to understand R in the full detail that God understands it in and know that the reason thereby understood justifies E. On the weakest reading, there is the ability to give some definite description D of R and know that the reason falling under D justifies E.
That there are evils on the inscrutability corresponding to the strongest sense of "know the justification" is not at all surprising given theism.
But on the weakest sense of "know the justification", as long as we know that God exists, we are in position to know that there is a justification for E, since that God exists entails that E is justified. And then we know R under the description "the reason or collection of reasons that justifies God in permitting E". And if we want slightly greater specificity, we might advert to some moral theory that gives us a characterization of the sorts of reasons that can justify a permission of an evil.
So for the Rowe argument to impress an intelligent theist who claims to know that God exists would require some in-between sense of "know the justification" that satisfies two conditions: (a) it is probable on theism that we would know the justification for every evil (or every evil that we have sufficiently investigated) and (b) the theist cannot plausibly claim to know the justification for every evil. These two conditions pull in opposite directions.