They wanted to use the hearing aids feature that Apple recently released but it is not available in India. They found a way to get around the geo restrictions and enable it.

Rithwik Jayasimha immediately went out with his dad to buy a pair for his grandma. “We came back home, we took them out of the case, and I was looking for the feature and it was just missing,”

I believe AirPods are the only earphones with a hearing aid feature so far, and because of how expensive hearing aids are, they are probably the cheapest.

He was Muslim not Christian so most likely never went to that church, unless he converted or something. But it does sound like it was religiously motivated:

the boy had told churchgoers who restrained him, in Arabic: “If they didn’t insult my Prophet, I wouldn’t have come here.”