First, Night Shade co-owner Jeremy Lassen has posted an open letter at Locus Online. In it he explains his reasons for making the deal with Skyhorse Publishing. He does not discuss the terms of the letter sent to Night Shade authors.
Second, Michael Stackpole does discuss the terms and why he won’t sign the letter in this post on his website.
I’m not going to comment at this time, other than to say that the loss of Night Shade is a nontrivial matter that will have a major impact on the field. Some time in the next week, I’ll try to put some thoughts together in a coherent manner.