They were from the leader of one of the largest religions of the world–which still represents roughly 17% of the world population. I'd say they are still relevant and part of what Numberwang refers to as a "modern view of the world".

BTW, I'm not saying I agree with the content of those lectures. Only that dismissing them because you think the modern world doesn't hold those views is silly. And, yes, I'm aware that more recent pontiffs have expressed different views.