Also, the reason women aren't turned on by shirtless men in religious paintings or statues is because it's a religious context. Even an atheist woman, who shouldn't care about committing sacrilege because she doesn't believe in it, won't be turned on by the shirtless men because there is sill an innate sense of what is appropriate, and what is inappropriate, impressed upon their hearts by God, despite their faithlessness. That's why they have no natural inclination to be aroused by a religious painting's image of a shirtless man.
And the reason the men are shirtless, and women are always fully clothed, is because it's natural for men to be shirtless as they are, naturally, the laborers. It gives them more free range of motion. There are no shirts, robes or cloaks to get caught on anything while working, and it helped keep them cooler during their tasks and hunts.