They're threatening "action" are they? Huh.
The director of your daycare, I hope you don't mind me saying, sounds like a dufus. I'd be concerned about leaving my child at a daycare where the director doesn't realize that chicken pox are most contagious before the spots even show up. And with such a mild case such as your dd's, even THEY didn't realize what they were.
Actionable, my caboose.
So, how about the next time your dd is exposed to the flu, one of the teachers comes down with a cold, pink eye is diagnosed in some baby, that you threaten THEM with some sort of "action?"
Better yet, find a better daycare. How insulting of them to threaten you. My feelings for them would never be the same, and I'd never feel comfortable with them again.