There can be many reasons for this. Check out the Program Development Department. Staff feels you expect them to treat volunteers with kid gloves, and, as a result, feel they have to accept bad performance from them. This will likely foster a feel of inequality and resentment. We include volunteers in our programs because there is important work to be done.
Volunteers are part of the best way to get that important work done.
Good volunteer management insures that the important work gets done well. Note that the emphasis is on the work, not the volunteers. Volunteers are vital, but only insofar as they contribute to the work. You can let this philosophy guide you not only in what jobs volunteers do but in how you choose and manage volunteers. Staff often needs to come to see you and the volunteers as catalysts for their own hopes and dreams.