Hi, coming out of the woodworks again because I'm from Rio and can explain this. This is literally a very popular thing and they do projections from time to time to support different campaigns, support countries in conflict and other causes that the city (and the church) supports.
Totally not disrespectful as many of the projects actually pay to do so - which is what the priest was implying he wanted a few days ago when he said that he was waiting for a reply from her team. Also, they revel in the profit that they make from the free advertisement that this is for the Christ the Redeemer as a tourist attraction, as this often guarantees many news stories about the projections.
I'm saying this because as a journalist who started my career with an internship at the biggest international news agency out there (don't want to say the name here) there were many times when I was sent there to literally report on this, get interviews from people on the streets and the priest who's in charge of the tourist attraction.
Anyway, I'm upset about missing out on all of this, but I would have never managed to get tickets for these concerts, so I didn't even try. Also, I wouldn't travel for a concert haha.