On Idyllic Isle, Pope Assails Moral Decay : Religion: John Paul preaches against the dangers of X-rated videos, materialism and racism as he wraps up his Asian tour.

John Paul II, the missionary Pope, ended another year of one of history’s most extraordinary papacies here Sunday, inveighing with his trademark Crusaders’ zeal against moral decay.

In a papal message that ricocheted from poor cane-cutters’ shacks to shining beaches strewn with topless European tourists, John Paul scored X-rated videocassettes, seductive materialism and what he denounced as the “blasphemy” of racism.

It was 11 years ago this afternoon that his cardinal peers, locked in secret conclave at the Vatican’s Sistine Chapel, plucked Karol Wojtla from the obscurity of provincial Poland to lead them as the Bishop of Rome.

Crisscrossing the globe on 44 foreign missions since then, John Paul--the world’s most prominent frequent flier--has changed the historically aloof face of the papacy, perhaps for good.

At a Mass on Sunday on the offshore islet of Rodrigues, John Paul, who firmly discourages elaborate observances of pontifical hallmarks, accepted flowers from four nervous Mauritian children, three girls and a boy, all of them born on Oct. 16, 1978.

This morning, the Pope celebrated a private anniversary Mass with Vatican aides and headed home.

An implicit message to the world’s 850 million Catholics rode back to Rome with the familiar stooped figure in a floor-length white robe: No matter in what corner of the world you live, sooner or later the Pope will come.

The explicit message here Sunday on a wind-swept emerald mote awash in the azure Indian Ocean was vintage Wojtla: No compromise on moral principles.

Mauritius, an island of 1.1 million people about 1,200 miles off the east coast of Africa, is a rare Third World success story: peacefully multiracial, democratic and prospering.

Dutch settlers came first to an island that had no indigenous population, but as John Paul rode among rustling palms and riotous bougainvillea, they had long since passed into Mauritian history as villains responsible for the extinction here of the dodo bird.

Today, the harvest of later colonial masters, Mauritius is an officially English-speaking but in fact bilingual nation where the at-home tongue is Creole French. Descendants of immigrants from India are a narrow majority among those from Africa, China and Europe. Mauritians are quick to note to visitors that their country is the only one of 47 African-area nations that became independent in the 1960s where political power is passed peacefully at the polls.

So, too, by leavening a traditional sugar-cane economy with export-oriented light industries and tourism, has Mauritius escaped the grim poverty that John Paul is accustomed to finding in Third World nations. Instead, it has become what tourist brochures boast is “the most cosmopolitan island in the sun.”

A sign of relative prosperity are the video rental parlors that dot byways of this tin-roofed capital. Not all of the movies for rent, Mauritian priests complain, are wholesome, though.

John Paul, on hearing that, needed no further urging.

“Do not confuse love and sex,” he told young Mauritians at a ceremony in a soccer stadium here Sunday afternoon. “Do not be led astray by images of love that are false: Some videocassettes . . . present relations between men and women that are a caricature of love.”