1) Some industries refuse to even consider it because it means they're effectively dead -- coal, oil, and a few other industries. They fuel propaganda because of this
2) Sheer ignorance
I say because it's very difficult and fragile to try and profit off a genuine catastrophe. We are indeed heading for a disaster (2C warming) even under quite optimistic assumptions about world politics and people accepting climate change and whatnot; if there is not enough action, if some technologies are not developed quickly enough, we are facing genuine catastrophe (I think there's far too much faith in a magical technological solution (rapid carbon capture) in current scenarios) -- 3 or 4C warming, where you start to talk about civilization collapse. This seems like a very weird thing to gamble with, specially since gambles require long term payoffs. If the economy and politics is a mess and there's general instability, how can you guarantee ability to monetize your bets?
No, I think most people are just genuinely not aware, willfully ignorant, don't believe humans could alter the climate, etc.
In a way it's good, because it means you can fight it to an extent with information.