These are not legal, not now; but 100 years ago, you wouldn't have been doing anything wrong. The law changed because the physical world changed, as did our understanding of our place in it.

A similar thing is about to happen with climate change denial, especially to powerful people and organizations who have consciously, purposely mislead the population about the dangers of climate change.

There are any number of lawsuits alleging this. As the cost of AGW becomes more and more clear, criminal prosecutions will become inevitable, one hopes.