The way The Dinosaurs extinct themselves is a simple analogy as to what we are doing to ourselves as well.
They destroyed one of the most important parts of their ecosystem in the name of profit (built a wax fruit factory over the swamp where the Bunch beetles mate) which caused an invasive plant to overgrow. Then by trying by taking out the invasive plant, they “accidentally” took out all the plant life on their planet. And finally, by trying to bring back the plant life, they accidentally caused a 10.000 year long nuclear winter dooming themselves to extinction.