Thanos's logic makes sense
The logic behind his actions does make sense. In the 2018 movie Avengers: Infinity the character Thanos claims that by wiping out half the universe he will save it from destroying itself. His argument is a simple one, less people means more resources for each person.
Thanos has a rather simple logic-get rid of half the planet in order to allow the other half to survive. It's a terrible circumstance, but in his mind he's saving the other half from living terrible lives. He's saving Earth from a terrible fate as a result of overpopulation and the resulting environmental problems. His intent is to be the savior of the planets he destroys. What he does is rather relevant to the world we live in today. We all live in fear of global warming destroying our planet. What if someone just came in and...fixed it? With one snap? We would adjust to the new life set before us.
As depicted in Avengers: Endgame, losing half of the world's population in an instant would be disastrous. The world is built to sustain the current population. Who would take care of all the buildings, all the creations that this world has made? Families would be lost and destroyed, and the world would fall into despair. Additionally Thanos has an absurd amount of resources at his disposal, in the Avengers films he is depicted as having a massive space armada and control over an absurd stretch of territory. Surely Thanos could use such resources to restructure earth, and other planets economic systems in such a way that would make them more sustainable. It is unclear as to why Earths population won't simply bounce back after the snap, even without the events of endgame, and the systems responsible for environmental desegregation still very much control the economies present in the MCU.
[P1] Thanos's logic makes sense. [P2] The world may be healed with his actions.