I thank you for the well-written, well-considered response regarding this matter. But I will respectfully disagree.
This site is successful because of the efforts of many people, both paid staff and a multitude of volunteers. When the volunteers are suddenly sent packing, no matter what the reason is, it is not too much to expect some form of communication. That communication could be as simple as a form letter thanking them profusely for their efforts on behalf of the community here and stating that admin has decided it's time for a new perspective. This would take microseconds and still acknowledge the contribution.
Volunteerism in all forms should be acknowledged and celebrated always.