Three very different images of the "Last Supper" - all, I would say, with their own integrity - all making a point for their time. The first one is of 'Bears', clustering around a drag queen (as Jesus). The second is also homo-erotic - but with women as the focus. The last is the well known Michaelangelo.
Depending on one's prejudices, each will have their own triggers for the viewer. 'Bears', for instance, are a particular sub-category of gay culture. The fact that most of us gay white men end up bears, is either a sad (or a happy) reality!
The wymyn in the second picture, I will grant you, look a bit as though they are extras for the set of "The L-Word". But pictured as they are, and clustered in this traditional pose, they make a particular point.
The thing I wonder, is not why would straight people find these images offensive - as they probably would. What continues to confuse me, is why Gay and Lesbian people would - (which, in my experience of showing them, they often do). The answer lies, I would think, in the complete dominance of explicitly hetero-normative imagery in the Christian church, even when the theme itself lends itself to homocentric interpretation, such as this one.