Mercule
Adventurer
I hadn't really thought about it, until just now, but this kind of bugs me -- or not. Cleric spells are granted by their gods and shouldn't work for secular Bards. On the other hand, a Wizard's Charm spell is probably fair game to anyone who understands magical formulae (including Bards).Spells and therefore Scrolls are not arcane or divine anymore. This distinction comes only from the Spellcaster itself. A scroll of Cure Wounds is cast as a divine Miracly by a Priest but cast as a Arcane Spellcaster from a Bard.
But, taking the Clerical exclusion too far means that a scroll from a follower of Pelor isn't usable by a follower of Hextor. That makes some sense (different herbs in their incense), but definitely limits Clerics on treasure. That might not be a huge deal, though, since they already have access to a huge swath of spells to prepare. Fair trade-off. Clerics can't use scrolls unless from the same god.
The opposite answer is that the magic is all in the scroll. Once you've got it written down, you just have to be able to read it. Well, why can't a Wizard use anyone's scroll, then? Surely a Bard doesn't have that unique of secrets compared to a "wise one". Just say that reading a scroll is reading a scroll -- you either can or can't. That might explain why scrolls, which are relatively cheap to scribe, aren't readily available. You don't want your nukes falling into the wrong hands. But, it could be a power issue, too, if players are allowed to scribe scrolls. The Cleric writes a few scrolls of cure wounds for each of the Eldritch Knight, the Wizard, and the Monk with the ritual caster feat.
Not sure what the answer is, but the current form seems to hit precisely in the "can't unsee" zone.