I can't tell anyone because it is risky for top administrators, or their partners, to publicly identify as atheist (some prefer "nontheist"). I'm not using my real name here.
Faculty members regularly announce themselves to be godless without consequence, but for an administrator—especially a high-ranking one—such an announcement could amount to professional suicide.
Typically, administrative appointments in academe—particularly senior positions like dean, vice president, and president, and particularly at state institutions—are highly political. While top administrators wield a considerable amount of power on their campuses, they are also vulnerable (like their counterparts in the world of politics) to people and forces that can undermine their positions and potentially jeopardize their careers.
My spouse has had a succession of administrative posts over the last few decades, and my experience is that in academe there is a kind of God Squad that monitors and polices administrators' beliefs and attitudes toward religion. The real danger for campus officials who reveal themselves as agnostic or atheist is retaliation from powerful donors, board members, alumni, or other administrators in the institutional hierarchy.