I will attempt an oddly serious answer, unlike my previous comment, since I feel this deserves one.

Sort of, and technically correct. Both the suicidal and the oil baron have no reason to care what happens after they're dead. But I don't know if that's relevant here.

Powerful people ruining the world do so because of incentives and... because they can. The only thing that will stop them and those that come after is meaningful societal change. Convincing people to participate in bringing about this change is important too, make no mistake, but it's because of what they can achieve united. It's voting, protesting, and building a world where the powerful can't screw over the world and everyone in it.

Hoping a change in culture alone will save the world is useless, because the rich and powerful will not follow that new culture. There's no trickle-up morals, and telling suicidal people they should be mindful of how they die (if serious) is barking up the wrong tree. It won't stop the oil baron from continuing to pollute more than everyone in this thread combined, nor will it make a meaningful difference even should the person follow your advice, because it's a drop in the bucket---and maybe the last one they'll ever make.

Trying to put it shortly, my point is that mentality is only the start. The world is broken (e.g. climate change is a thing), not just because of mentality, but because those high above do all in their power to stay there and shape the world in ways that suit them. Changing people's mentality is good, but is "use hydrogen instead of helium" really the last thing a suicidal person should have to hear from you?

Of course, this is a meme community in the end, so apologies if this comment was unnecessary because no one is seriously saying that. But anyone who thinks so should also be able to read my previous comment in its intended humor as well.