are we to believe that all ( or the majority ) of things that happen are because whales wanted so ?
In a sense, yes. But only because the people with the most bitcoin have the ability to move the market with the least amount of effort. If bad news comes across the market is moved most because the people with the deepest pockets ("the whales") are making the biggest moves.
Bitcoin is very volatile, and could be hard to finding a reason of all prices fluctuations
Absolutely, and bitcoin is global which means that it's hard to pin point any one new story on the actions of the entire global investor base.
Who the hell are those people. I mean manipulating betting sites prices, altcoins, even stock prices of companies, I could understand. So are these guys like in perfect sync around the globe, just dictating what happens next, while we are simple passengers completely at their will? Am I being naive ?
"The whales" is a figure of speech, a euphamism, a way of referring to anyone that has a lot of bitcoin but there's no formal definition of how much bitcoin one needs to have to be considered "a whale". It isn't a defined group of people, it's not a club. And a few whales may talk to each other but only because reach people hang out.
To your point about being a passenger, yes, most of are. But the whales aren't trying to all coordinate their piloting of the train. In most cases the whales are companies because companies have the most wealth, period.