There is a vocal minority of people don't believe the overwhelming scientific consensus about global warming, and they downvote, flag, and argue in these posts

There is a vocal minority of people don't believe the overwhelming scientific consensus about global warming, and they downvote, flag, and argue in these posts aggressively. Consequently, the topic gets the reputation of being "divisive". It's playbook how to make an important topic taboo, and an extraordinary success for the people that don't believe the overwhelming scientific consensus about the impact of modern human activity on the climate (or believe it, but profit from the status quo).