If dinosaurs were created alongside man, why did they go extinct?

The weather changed drastically because of the flood. Before the flood you had a fairly pristine environment, which is why men lived so long; Shem was six hundred when he died, and after the flood the ages drop rapidly to four hundred, then two hundred, so something clearly changed. Either the physiology changed to produce a more rapid decline in age, or the environment got colder and lost pressure, or both. With less pressure, a colder climate, and less vegetation, any organic specimen is going to be under drastic stress, and creatures that needed a lot of food, like the dinosaurs, could starve; lizards in particular need a warm climate. So a combination of factors drove them extinct. But dinosaur tracks are found together with human tracks, that cannot be denied, including human prints in Cretaceous sand that were shown to skeptics like Dawkins and Gould, who admitted at least one was genuine and then walked away, which shows the problem is the heart of the man, not the evidence.