I am not sure if this is a serious question, but I'll bite in case it is.
Without DRM Netflix's business would not exist. Nobody would license them any content if it was going to be streamed without a DRM.
They just want DRM because it makes them even more money. Or at least they think it does. I have yet to find a single TV show or film that isn't available on Bittorrent so I don't think the DRM is actually preventing piracy in the slightest. I guess they want it in order to prevent legal tools from easily working with videos, e.g. for backup, retransmission etc.