You managed to liken this issue to both global warning and political corruption without taking the next logical step to conclude that, like those problems, this is an inevitable consequence of capitalism. As long as people have a vested financial interest in destroying the environment, they will. As long as people have a vested financial interest in engaging in political corruption, they will. As long as people have a vested financial interest in spreading bad information, they will.
In all cases, the so-called bad actors are just being capitalistic. Wealth and riches are lauded by society, billionaires are practically worshipped for their greatness, and becoming fabulously wealthy comes with a vast array of privileges and benefits. Behind all of these social evils are billionaires of one stripe or another, perched atop the pyramid of capitalism. None of this should come as any surprise, nor should we blame individuals for engaging in behavior that capitalism ingrains in them as being totally appropriate.
A democracy clearly cannot function when the people, tasked with choosing leadership and making decisions in public elections, have no ability to discern the truth about anything. If disinformation is an inevitable consequence of capitalism in a world where people can make money off of duping others, then it stands to reason that democracy and capitalism simply cannot coexist. People with greater financial means can lock in systemic privilege for themselves by leveraging their resources to keep those of less means ignorant and compliant.
And, of course, the well-known study by Gilens and Page bears that out in black and white. In other words, disinformation, political corruption, and climate change are all the same problem, and they all exist because capitalism is a system that is fundamentally based on inequality and disenfranchisement. To expect reason or justice within such an economic structure is illogical, so, if you want to really take up the fight against disinformation, it starts and finishes with tearing down the capitalist apparatus.