A quote I heard just today: "I see better than I hear." That is, show me by your actions. If the words don't match the actions, I'll believe the actions.
(The quote was from T. J. Houshmandzadeh.)
If you use this logic to "disprove the elites", could you answer the question I posed to GP? Why do you think the elites care about their properties? Why wouldn't they buy them to get another good 10, 20, 30 years out of them before it's too late?
If they really believed their rhetoric why wouldn't they build on an inland ridge and pipe the water in?
I think they're pointing out the disconnect between espousing the idea that we're on the verge of rapid, irrevocable, global calamity on one hand, and both directly contributing to that and buying beachfront property. It's easy to see why someone already predisposed to believe misinformation around science might look at that assume that it's all a scam of one form or another.
As AnimalMuppet said actions speak louder than words.
“Your actions speak so loudly, I can not hear what you are saying.”
― Ralph Waldo Emerson