This is actually addressed in the books. There's a part when Harry is whining how nobody believed him when he said Voldemort was back and Hermione basically goes "Dude, you convinced Cedric to touch the cup at the same time you did, then you both disappeared and you came back with his dead body screaming about an evil wizard who has been dead for more than a decade. I only believed you because I'm your friend."
The movies also frames Dumbledore as a hard boiled unhinged detective who slams people against walls and shakes them down for information, whereas the book totally missed out on that great aspect of his personality. Swings and roundabouts
Definitely, Dumbledore is much better in the movies. I think the books overexplore his relationship with Voldemort and he comes off a bit daft. All of his
interactions with Voldemort are like:
Voldemort: Genocide is cool, right?
Dumbledore: No, it isn't
V: You're right. Anyway, theoretically, how can I become more stronger?
D: Are you gonna do a genocide?
V: high pitched Whaaaaat...?! Naaaaaaaah! I would never do that!
It's been a long time, but I very much remember it being played as the powers that be are simply afraid to acknowledge that V is back. They do attack Harry's story some to help justify keeping their heads in the sand, but that didn't seem like the point to me.