Okay, I just dug up the following quote from Morrigan at the Temple of Mythal. This is when she spots the statue of the Dread Wolf:
"...is as blasphemous as painting Andraste naked in the Chantry."
This could be a question of semantics. When I heard that line, I took it to mean "painting Andraste while naked in the Chantry." In any case, it doesn't mean that depictions of Andraste are considered blasphemous, only that either painting a naked image of her while in the chantry, or a naked person painting her while in the chantry would be considered blasphemous.
I would consider her example to something akin to "getting drunk at church."
In any case, this is all moot, since the Inquisitor doesn't carry the staff around while in the Chantry. For one, the Inquisitor is not in the Chantry. The Chantry specifically rejects the Inquisitor in the opening scenes of the game.
For another, the cited example of it being inappropriate was specifically referring to carrying the staff in a place of reverence. The only two occasions I can think of that the Inquisitor would actually carry a staff while in a place of reverence are the church in Redcliffe (a brief scene cleansing demons) and when Leliana and Quizzy go to a chantry location seeking what Divine Justinia left for Lels.
The rest of the time, the Quizzy isn't at church, or in a place of reverence.