Yeah, I understand where you're coming from, but like what I've said before, any self-respecting christian who knows they have an issue with something should be taking action to take care of that problem, part of that is knowing what their triggers are. If they know their going to be triggered by something like that, they can and should look away, or better yet, just avoid. I'm sure an avid museum and art fanatic would know where they should and should not expect to see something that would trigger them. From my own personal point of view, by someone having an issue with lust and pornography that ends up stumbling because of nude art work, it's far to easy to use the reasoning you mentioned for them to put the blame on someone else which is extremely dangerous for them.
That's not to say you're wrong by any means. As christians we should do everything we can to avoid hitting people's triggers, but everyone is affected by something different and it's very likely we won't always avoid that. Reading ijustwantthetruth's posts about her own artwork I think she did a good job of making something she felt she should, while still being mindful of anyone who could be affected by it, hence the reason she made this post.
I apologize if I'm offensive in anyway, I don't mean to be, I'm just trying to explain how your perspective could be dangerous for someone involved.