The Madison-based Freedom From Religion Foundation has sent a letter of complaint regarding the recognition of Good Friday as a campus holiday by fifteen of the state's sixteen technical college, apparently pursuant to a collective bargaining agreements with instructional staff. The FFRF argues that closing on Good Friday (not just calling the off day "Good Friday') is inconsistent with a 1996 decision of the Western District of Wisconsin invalidating a state law that mandated the closing of public facilities for the purpose of worship.
The prior decision seems distinguishable to me given the statute's explicit reference to closing for a religious purpose. It's hard, in light of that, not to see the statute as violating current Establishment Clause doctrines.
These cases tend to turn on some ascription (often fictional) of a religious or secular purpose to the state. FFRF will have to show that the recognition of the Good Friday holiday has a religious purpose or amounts to an endorsement of Christianity. It may well lose because a court will conjure some secular justification for recognition of the holiday, e.g, that the day also known as Good Friday has become a traditional opening to the spring vacation.
My own view is that there is no sense to this. Spinning some secular justification for what is a religious holiday is unseemly, at best, and disrespectful of the religious tradition in question, at worst. The colleges are recognizing that this is a day with religious significance for most of its employees and is responding to their desire to have that day off.
My own view is that this ought not to raise Establishment Clause concerns. While it may raise an issue regarding accommodation of the religious holidays of other faith traditions, it does not advance or endorse religion in a way that ought to be constitutionally prescribed. A non-Christian suffers some burden because a state facility is closed on a day when the majority is observing a religious holiday, e.g., annoyance at the unavailability of certain services or confirmation of one's minority status.
But this seems to me to be indistinguishable from the harm that religious adherents claim when the state, for secular reasons, acts in a way that is inconsistent with their beliefs and practices. It cannot be prevented in an even handed manner and we ought not to try.