Stupid in ways you may or may not realize. These people are making some serious future predictions that just don't come true. This isn't about picking the wrong lotto numbers or sport team to win. These people try to predict future events while literally affecting the lives, and rarely in a good way, of a good chunk of the human population. These predictions that don't come true and people's lives are that much worse and some cases wrecked.
The Bible calls these type of people 'false prophets' and we know what used to happen to them before Jesus caused everyone to take a long hard look in the mirror. While it seems like there's nothing we can do there is actually one thing that can be done.
What was the first thing Jesus did when he stepped onto Temple Property? It sure wasn't saying hello to everyone that He is there to help. He didn't immediately pray to His Father. . .no, He grabbed the nearest whip, started overturning tables, and chased out the people who didn't belong on Temple Property.
That's what we need to do to these modern 'false prophets'. First forgive them for their lies. . .but if they don't/won't repent then chase them out of the public square, political discussion, and matters of making policy. There's at least one or two examples of the Apostles doing concerning false teachers inside churches. They told these people to get lost and never return unless they repent of their sin.