The secularism that is a root of a systematised willingness to kill some sorts of weak and dependent people (Evangelium vitae, n. 21), or that takes an intolerant form in denying the legitimacy of using Christian criteria when making political decisions (Doctrinal Note on Participation of Catholics in Political Life n. 6), is not to be confused with a healthy secularity or respect for the secular.
http://www.ewtn.com/library/ISSUES/SECULAR.HTM