We have no idea of a person's spiritual life, and parading to church does not necessarily reflect how one feels about God, church, or religion. Many people find it preferable to keep their spiritual practices private. William has no public role related to the C of E at present. If he and his family choose to spend Easter away from the public eye, then that is what works best for their family and there is no reason to criticize. Further, I suggest that for a lot of people, seeing the BRF going to church on a major holiday has more to do with photo ops and fashion reviews than any recognition of spiritual leadership.