It can still happen without any central control. Popular culture changes. People generally don't respect churches as much as they used to. That's not a conspiracy theory. That's kids rebelling against their parents and wanting to stamp their mark on the world.

How can you talk about a "lack of respect" when more than a billion euros have been raised within a day to rebuild it?

Also keep in mind this conspiracy theory is often followed by goalpost-changing along the lines of "well, obviously I didn't mean that they're all actually in a conspiracy, it's because they've been influence by [other conspiracy]", generally leading either to an infinite regress of adjusted claims, or talk about cultural Marxism claptrap and claims about how the Frankfurt School academics somehow nefariously orchestrated the next hundred years of global social change in the 1930s.