Pope Benedict XVI rebuked Western societies — including his fellow Germans — for often shutting their ears to the Christian message, insisting Sunday that science and technology alone cannot combat AIDS and other social ills.

Addressing 250,000 pilgrims at an open air Mass in Munich, Benedict said modern people suffered from "hardness of hearing" when it comes to God and complained that "mockery of the sacred" is viewed as an exercise in freedom.

It was the second day of a pilgrimage to his Bavarian homeland, a six-day trip filled with nostalgic meaning for Benedict as well as for his liberal flock in Germany.

He said that faith must come first before progress can be made on social problems such as the HIV/AIDS epidemic in Africa.

"Hearts must be converted if progress is to be made on social issues and reconciliation is to begin, and if — for example, AIDS is to be combated by realistically facing its deeper causes," Benedict said.

The message was consistent with church teaching that sexual abstinence and faithfulness to one's spouse — and not condoms — are the best way to fight the disease.

"Put simply, we are no longer able to hear God — there are too many different frequencies filling our ears," he told the crowd, which stood quietly shoulder-to-shoulder on a field on the outskirts of Munich, where he served as archbishop from 1977 to 1982.

"What is said about God strikes us as pre-scientific, no longer suited to our age."

"People in Asia and Africa admire our scientific and technical progress, but at the same time they are frightened by a form of rationality which totally excludes God from man's vision, as if this were the highest form of reason," he said.

Faithful waved yellow-and-white Vatican flags and the blue-and-white diamonds of Bavaria, while Mexican, Croatian, Slovak and Polish banners also fluttered above the crowd. Munich police spokesman Peter Reichl said the crowd numbered around 250,000.

Rev. Chris van Damme, 38, a native Belgian but Austrian-based priest who traveled from Bregenz, Austria, with a group of 13 teenagers, said he appreciated the pope's clear words.

"Young people need direction, and the pope gives them that. He tells it to them like it is," he said. "This visit is important for those who are a little distanced from the church."

The need for Western Europe to return to its Christian roots is one of Benedict's favorite themes, and he is repeating it during his visit to his native country — home to a shrinking and liberal Catholic Church and a highly secularized society. More than 100,000 people leave the German church every year, and only about 14 percent attend Mass on an average Sunday.

Benedict criticized the German church for putting social service projects and technical assistance to the poor ahead of spreading the Christian message. African bishops, he said, told him all doors were open to them in Germany when they wanted to talk about aid projects, but added they were greeted with reservations when it came to evangelization.

"Clearly, some people have the idea that social projects should be urgently undertaken, while anything dealing with God or even the Catholic faith is of limited and lesser importance," Benedict said.

In the crowd, Gerda Holzinger, 57, said that since former Cardinal Joseph Ratzinger became pope last year she was seeing a new side of the conservative former theology professor, who left Munich in 1982 to become the Vatican's chief doctrinal watchdog.

"Cardinal Ratzinger was for us a stubborn theologian; now he is opening up, and a completely different person is coming out," she said. "I find him good. He sticks to the old values, which have been good for 2,000 years."

On Monday, Benedict plans to make a brief visit to Marktl am Inn, the small town where he was born, and to Freising, where he was ordained a priest. He will also visit Regensburg, where he once taught theology; he still has a house in the city, and his brother Georg, a retired priest and choir director, lives there as well.

Police said that vandals tossed balloons filled with blue paint on Benedict's birth home in Marktl am Inn sometime early Sunday. The damage was not serious, and Vatican spokesman Rev. Federico Lombardi dismissed the incident as "really secondary."