The artwork is a critique on the common hypocritical, racist and sexist sentiment many christian people hold. The artist clarifies it's based on experiences growing up queer in a christian environment.

If anything, this could upset people who don't want to admit to being bigots. I suppose pointing out systemic issues in certain groups of society could be seen as offensive. But the right approach to solving that is not to shove it under the rug. This public school messed up there.

By the way, the work is not explicitly lesbian, perhaps that's describing the artist themselves. Advertising it as such seems like a misrepresentation.