I don't even see how climate change, or famous people talking about it, can be seen as a conspiracy theory anyway, as there's so much evidence.
Plus, how many people would need to collaborate in the same lie and not one of them leak the lie? But then I ask that question about so many conspiracy theories!
Some just find it easier to bury their heads in the sand, or say celebrities are hypocritical for talking about climate change while getting on a plane. While there might be some hypocrisy it's still spectacularly missing the point about climate change being an issue. Saying "I'm going to ignore it cause some film star does" is akin to a child's mentality.