Why do you people make light of the destruction of your own civilization?!
Shouldn't you be doing something to stop it?!?
ANSWER: This is a question with two parts.
A1. Gallows humour has a long noble history; it may well be the most authentic form.
Once all hope is lost, when you're up against the wall and the firing squad are raising their weapons, there's something to be said for looking your fate in the eye and saying "well, fuck you too..." And you never know (see illustration of concept from Saving Private Ryan).
A2. Like many of your species, you're in denial. You apparently haven't come to terms with the fact that we're already dead. You need to make the cognitive leap beyond hope. Take a deep breath and find that place within you. It is only once you recognize that any intervention can amount to nothing more than a miniscule short-term deferral of the inevitable, that you will find the true freedom and inner-peace that comes from facing up to reality, and embracing hopelessness. Only then will you truly appreciate what you've got. Like Jesus said, in one of his rare moments of lucidity ...
"Then you will know the truth,
and the truth will set you free."