You're right: Someone should corner them on why "Netflix Original" content isn't DRM free. (Or why they still restrict access and subtitles based on region, for "Netflix Original" titles.)
DRM for Netflix is about putting up barriers. Just like Amazon convinced publishers to go with Kindle DRM, giving Amazon the power in the end. By encouraging DRM, it's harder to compete as it is one more thing to do that Netflix already has. It's not as powerful as Kindle's lockin - content licensing is a bigger deal. Apart from that? Well, Popcorn Time provides a much better experience than Netflix. (Proper subs, force HD, use better player to normalize audio ("night mode") or otherwise tweak viewing, no messing with proxies, etc.) My wife and kids are already starting to use PT, even when the same content is on Netflix. Yikes. (Torrents + put.io was already pretty slick, but slightly more difficult (2 apps, one extra click).)
Anyway, it's going a bit off-topic here, except may be it's a good reminder that DRM should never be used since it only punishes legitimate customers and does nothing good.
If I were Netflix, I would use my own content (such as House of Cards) to demonstrate that it's possible to go DRM-free.
That's primarily my point, but I don't agree that DRM in necessary for business. Music is sold DRM-free, games are too (GOG). So there is no reason why video can't be. Someone just have to break the sick status quo.