The graph I linked has a lagging indicator factor to be sure.
Tobacco consumption from 1970s to today has dropped for obvious reasons.
Lung cancer dropped from 1990s to 2006 or so in a highly correlative rate to tobacco consumption. Which is great news!
But suddenly since 2006 lung cancer rates have dramatically increased. It's now above the lung cancer peak in the 1990s.
The conspiracy mainly being they dont show you the huge increase since 2006 and keep their graphs clean.
The allegation that tobacco toxicity kept lung cancer in balance is possible but certainly unproven.
Instead what my other link tried to show is that perhaps tobacco use isn't the boogeyman and hell you probably noticed governments have given up on the anti-tobacco game.
We now know what's causing it but what's the consequences to society if we published? Oh man I could see the collapse of society so quick.
As for the other claims, I haven't done any research, but it sounds vaguely like Simpson's paradox could be starting to dominate the graphs, so they stopped publishing them. (i.e. there are other confounding variables that now dominate, so it is not worth the research time and money to continue collecting that data specifically for smoking rather than looking for new causes)
Conspiracy or a lagging indicator of reduced cigarette consumption?