he's not just "saying", there's math involved. If you don't want to check the math... how much do you know about human psychology? If I tell 1000 random people a huge secret, like where I've hidden an atomic bomb, or a billion in gold bullion, or something similar, and then threaten their lives (and their relatives) if they talk, and give them money to keep quiet, etc etc... do you really think all 1000 will keep quiet forever? No accidental spills, or deathbed confessions?
Now increase the number of people. 5000, 10,000... at some point the 'secret' becomes completely impossible.

Of course conspiracies exist, but they are boring ones - small, tedious, sordid... embezzling, adultery, misapropriation of funds, bribes to build a mall, or buy a business, or keep quiet about a boss who raped a secretary. Crap like that. Nothing exciting or grand. And even most of that comes out sooner or later.