If we read between the lines, Paul may be saying, "You people are better than I am in your devotion to spiritual things."
Instead of "religious," the King James Version uses the word "superstitious," which has undergone what linguists call "semantic drift." In Shakespeare's day and King James' time, this word did not have the negative association as it has now.
From the context of the account in Acts 17, it becomes quite clear that the apostle Paul was not, as some Protestant theologians like to characterize him, a feisty, wrangling, argumentative hothead. If that were the case, the philosophers of Athens, who vastly outnumbered him, could have made short work out of this smart aleck. Obviously, from their attention to his speech, they did not think of him this way.
David F. Maas
Godly Tact and Diplomacy