Trump didn't mean for Paris to send flying water cannons to the cathedral. He put that 'idea' out there so some profiteers would consider it, come up with a flying water cannon that every city can buy where a Trump tower exists. That is what that comment is about.

The normal president would state concern for the city, sympathy to the Catholic Church for the pain the community is feeling and offer help. No president would see a fire at Notre Dame Cathedral as a capitalistic opportunity for a dreamscape for tall towers.