Aquinas is worth reading. He has stood the test of time. And even where he errs, you can learn more from the errors of a great mind than you can learn from the truths of a small mind. You can see a whole lot farther standing on the shoulders of giants.
Evangelicals have largely misinterpreted Aquinas, and they have placed on him views that he did not hold.
For some, the belief in a Young Earth seems to be based on a kind of intuition or faith in what they believe an omnipotent God should do. It reasons that if God is all powerful, then certainly He would not have taken millions of years to make the earth.
Pluralism is denied logically; inclusivism is denied scripturally, and that leaves us with exclusivism... you have to know that Jesus died and believe in it in order to be saved.
Even Martin Luther and John Calvin believed that the Roman Catholic church, up to the Council of Trent, was basically orthodox - a true church with sound fundamental doctrines as well as significant error.