this assumes that the people on the internet are arguing in good faith. they aren't in a lot of cases. the problem i have is willful ignorance and the associated culture that promotes the people that spread lies.
or, see this comic: https://imgur.com/T8egYQl
But isn't the number of people reading a problem per se? The "deniers", those who keep shifting their arguments until they've gone full circle to the starting point, are not trying to convince you- nor you are trying to convince them. They're competing with you for the attention of the reader, trying to fill the space with the illusion of an argument.
Remember, the point of debating publicly isn't to persuade the person you are debating, it's to persuade the people reading the debate.