Celebrities including Madonna and Selena Gomez are using social media to voice their opinions on the Israel-Hamas conflict. (Reuters)

Most of the time, when celebrities call for peace in the Middle East, all it produces is a war of words on social media.

Madonna became the latest to experience this all-too-common paradox when she posted two photos of half-naked backup dancers men with the Star of David and a star and crescent symbol (to symbolize Islam) painted onto their six-packs.

But why, you ask? Because, Madonna.

First, there is something strange about painting two religious symbols on naked bodies, particularly given the importance both religions place on modesty. Madonna, as we all know, has been known to dabble in such things before (“Like a Prayer” anyone?).

But the comments on the photos more closely resemble a cesspool for Internet trolls than a haven for peace lovers. I’ll leave you to check them out for yourself because The Post is a family newspaper multiplatform media outlet.

Most celebrities who dare to dabble in international relations inevitably elicit eye-rolls at best — and, in the case of the ongoing war in Gaza, the worst angry repudiations from both sides of the conflict.

It happened when One Directioner Zayn Malik tweeted #Freepalestine to his 13 million followers.

Earlier, NBA player Dwight Howard issued a #Freepalestine tweet and immediately regretted it. He then pointed out that he has long recognized the perils of dabbling in real world affairs: “previous tweet was a mistake. I have never commented on international politics and never will,” he noted in a subsequent message.

When Rihanna tweeted — then subsequently deleted — her own #Freepalestine message, she didn’t bother with the “sorry I don’t do international politics” excuse.

Instead, she claimed it was an accident and went with a less controversial message: “Let’s pray for peace and a swift end to the Israeli-Palestinian conflict! Is there any hope?…”

For celebrities, there probably isn’t any hope.

Even when they’re not sending out symbolically questionable messages about peace on social media, they aren’t safe from recriminations.

A group of Spanish stars including husband-and-wife actors Javier Bardem and Penelope Cruz released a letter calling for an end to the “bombing by land, sea and air against the Palestinian civilian population in the Gaza Strip.” The response was predictably polarized.

“What do Javier Bardem and Penelope Cruz know about genocide?” asked an opinion columnist in the Jerusalem Post. “Well, apparently enough to know that Israel is committing one in Gaza against the Palestinians and Hamas.”

“But seeing their public declaration to that effect, I wondered about their immersion in the subject,” the columnist continued, all snark intended.

Both Bardem and Cruz released subsequent statements further clarifying their stance and noting that they had been condemned as “anti-Semitic.”

The truth is, we elevate celebrity opinions; so it should come as no surprise that famous people occasionally want to use their celebrity to speak out on the more controversial stuff.

It’s usually perfectly acceptable for celebrities to speak up about water issues, AIDS research and humanitarian aid for the developing world. These are all things on which most reasonable people agree.

But they dare not have opinions about politics or gay marriage, as Carrie Underwood, Matt Damon and countless others have learned.

The backlash — even from their own fans — on social media and elsewhere also shouldn’t come as a surprise. Fair-weather fans aren’t a new phenomenon; just ask the Dixie Chicks.

But is it time to acknowledge that celebrities are human and some of them — shirtless dancers or no — have thoughts and opinions of their own?