Yes, smoking is bad for your health and tobacco companies famously worked to cover it up. Interestingly, they employed scientific studies (with credentialed scientists no less) in their attempts to downplay the risks of smoking.
The US gov. also employed scientists to buttress cannabis prohibition. Funding was made available for researchers who toed the line and denied to those who did not. After millions of arrests, CBD is now touted as the latest panacea. The DEA still lists cannabis as a schedule 1 substance with "no therapeutic value".
Then there are the experts who sold us the war in Iraq. Skeptics were labeled conspiracy theorists.
Media outlets parroted official narrative of the war in Iraq, the war on drugs and other elite promotions.
As a hypothetical, consider that climate change and COVID both give license for increased central planning. Observe that the research is funded largely by the same institutions which will gain power when these objectives are reached. Putting aside the contentious debate, both sides should be able to accept that there is a conflict of interest here.
Yes, we should look to history. There is a long history of experts, technocrats or otherwise anointed individuals attempting to smear dissenters. Attempts to claim a monopoly on truth are regressive. We are all worse off for it.
Science is not a system of belief. It is a system of rational inquiry. Those who seek to shut down discussion by labeling dissenters as "science deniers" deserve to be scrutinized.
https://maps.org/news/media/2986-war-crimes-suppressing-scie...
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1470431/
https://en.wikipedia.org/wiki/Hans_Blix
https://norml.org/blog/2008/06/24/still-more-on-cannabis-can...
https://www.nbcnews.com/news/us-news/one-doctor-vs-dea-insid...