Well, its not really bagging on it. The program is great, but its like asking a teacher that doesn't know you to write a LOR. Sure the teacher can write a letter that'll go something like, "Siggy got a __ in my class, blah blah blah." Compared to a volunteer group with a lot of members and almost no direct oversight (since your helping out the CNA, nurses, and techs, and they, not the administraion of the program, provide the oversight), the LOR would come out as, "Sure, he volunteered for ____ hours and blah blah blah. I'm sure adcoms have seen enough of these letters before to know that the letter themselves means nothing special.