One of the many influences of secularism in society is the prevalence in the concept of individuality.
It's no longer about "us," as it was during the Greatest Generation, where people rallied for a cause greater than themselves and were willing to sacrifice for a common good, it's about "me."
In this "me" society, pride and self-interest have replaced humility and self-giving. What "I" think is more important than what others think; and that unfortunately includes God. Truth is distorted and molded, according to personal perspective and the individual decides right from wrong.
Of course, if you come to think of it, isn't this exactly what the Original Sin was? Humanity wanting to be like God and being able to determine good and evil and right from wrong. After all, Adam and Eve ate from the "Tree of Good and Evil" because they wanted to be like God (see Genesis 3, verse 5) and decide right from wrong.
The Pew Forum Study on Religion, which tracks religious trends each year, shows that more and more people leave the church they were raised in for another (according to how the teachings of a particular church conforms to the believer’s individual perspective).
Although, the Catholic Church continues to grow in the U.S., being the largest Christian church in the nation (67 million strong), it also is the church that loses the most followers each year.
In a recent commentary, Fr. Robert Barron addresses this phenomenon and why it is important for the faithful to remain in the Church.