I don't think anybody seriously thinks Climate Change is a myth. There are just too many people who are too selfish to care.
The US has a president that has routinely supported the "it's a myth" viewpoint [0], which increases the visibility and credibility of climate change contrarians regardless of their motivations.
[0] https://www.factcheck.org/2024/09/trump-clings-to-inaccurate...
What is the valid heuristic is that what you see on it all the time is clearly what someone wants you think.
Someone in real life that cites rando social media too much is probably on their phone too much or themselves in a non-genuine activity group.