My guess is that the US has enough information about the illegal spying our EU governments do to us, that no elected politician here in Europe would risk to have that leaked.
?
Millions is probably overstating it though.
FTA:
"An estimated 854,000 people, nearly 1.5 times as many people as live in Washington, D.C., hold top-secret security clearances."
Which might place a rough estimate of tens to hundreds of thousands (depending on how many would be in the Military, work directly for the Govt, or work on other programmes)