Just when you think anti-Israel terrorists cannot sink any lower, extremists with hate in their hearts kidnap three teenage Israeli boys who are guilty of nothing. And then Gazans celebrate by handing out candy to their children.

Gilad Shaer, 16, Naftali Frenkel, 16, and Eyal Yifrach, 19, were abducted June 12 while hitchhiking on a well-traveled road near their home in the Gush Etzion bloc.

Condemnation came swiftly from the Obama administration, the Israeli government and even from Palestinian Authority President Mahmoud Abbas, who said the boys “are human beings like us.” Abbas is in a tight position — Hamas almost certainly was behind this heinous crime, and Abbas sits in a unity government with the leadership of this criminal group.

Israel acted swiftly. Security forces have swept the West Bank, arresting more than 150 Palestinians suspected of having ties to Hamas and other extremist groups. The country has mobilized, and the Netanyahu government will do everything in its power to find the boys, return them home safely and mete out severe punishment to the kidnappers.

But something ugly is lurking in the background: an insidious lack of concern from certain quarters over the fate of these particular boys. Because they happened to live in a West Bank settlement, apparently they were fair game.

No. They were guilty of hitchhiking while Jewish.

It took a full five days, and some very loud complaining from Israeli officials, before European Union foreign policy chief Catherine Ashton spoke out against the kidnappings.

This is not to doubt Ashton’s sincerity, but her hesitation reflects a sentiment widespread in Europe and elsewhere that so-called settlers fall into some “other” category, unworthy of the customary protections societies provide.

Let us be clear. No matter one’s opinion about the legitimacy of Israeli settlements in disputed territories, children are off limits. Period. Their place of residence is immaterial.

But this is Hamas we’re talking about, one of the most ruthless, murderous gangs in an already very tough neighborhood.

The Palestinian Authority is cooperating with Israel in the search, which is a good thing. But this case reveals the flaws in accepting the Fatah-Hamas unity government that now rules the PA. This is what a modern-day Trojan horse looks like.

Meanwhile, all we can do here is hope and pray for the safe return of the victims. Bring our boys home, now.