I'm kind of with you on this, volunteer has always been something done of a persons own volition without recieving compensation. Even when someone is holding a sign saying "will work for food" they are trying to barter, not voluneer for something.
I think as I get older I just get less willing to accept new uses for existing words. I grew up without a lot of social interaction so I may just not fully understand, or maybe it's just something that was lost in translation.