You frame it the way you do to liberate yourself from meaningful action. You would rather rant and rail, as you say.
Mini has it right, the majority of people are already inundated with media. Thousands of times per day they are bombarded. What's more interesting? The latest cute kitten on Facebook, the invite to a party this weekend.....or a screed some angry person posted? Hint, it's not the rant about global warming. Most people immediately got turned off. The messaging is absolutely critical.
Curious, how many "paid shills" do you encounter IRL on a daily basis? If you're running into these people all the time you must have a unique job that brings you into contact. Arguing back and forth online probably isn't very effective. Normal conversations over a beer, dinner or coffee are 100x more effective than any anonymous message board.
You still don't get it. Doomsday is around the corner for us, and already here for millions more. I can't help it if you refuse to take in what the scientists are actually saying, but here's a quick summary: If we don't resort to drastic action right now we're all fucked.
Food shortages, droughts, drowning cities, mass migrations, dwindling water resources and wars
We've already got a lot of that. Why are you worried about rich people who live in coastal areas? Aren't those rich fucks part of the problem? Notice the color isn't quite green. What is the reaction the general public has when they see this IRL?

Most people laugh or shake their head thinking the person is a loon. Shouting we're all doomed is very nihilistic and a rather miserable way to live.