As a cord-cutter I understand your point. However, Roku has never been advertised as a cable TV substitute. Roku has relationships with some of these content providers. The value of these channels is that they have some free unlocked content and if you do pay for cable TV, you can then be a "cord-shaver". You can eliminate the costs of renting cable boxes for secondary TV's in the home. Why pay a rental fee for a cable box for the guest rooms, kids room, etc.?
My son loves his Roku on his bedroom and I have a Sony BR player with streaming apps in my guest room. If I was paying for cable, I'd just be paying for one box for the main TV and just use Roku and other streaming alternatives for the other TV's in the home. You can certainly save money this way so having "authentication" required Roku channels is not a bad thing for some.
I use QAM to get my locals free from Optimum through my coax line and some of these channels do authenticate with my Optimum ID and pw. Between all my locals via QAM, SimpleTV, EyeTV and TiVo (OTA DVR solutions), PLEX, XBMC, casting, subs to NetFlix and Hulu+ and other free streaming content from Roku, Sony BR, Equiso Android TV and RaspberryPi XBMC I am able to get most of what I watched before for about 1/3 of the cost.
I have certainly spent a lot of money and time for all cord-cutter gadgets, devices and time doing research to get my setup "just right" but it has been fun and I have recovered every penny and then some in savings over time in comparison to every other person out their paying for traditional TV services.
Roku is not a free cable TV alternative, but if used right it can provide a lot of the content you could get from your cable box.
2xRoku2 XS,Roku1+SE,Logitech Revue GoogleTV,Raspberry Pi+XBMC,Mac Mini+EyeTV DVR+RabbitTV+PLEX+Kodi,TiVo Premiere,Sony BluRay+streaming apps,Equiso Android TV,FireTV,Nexus player,Simple.TV Local TV:QAM from ISP coax line. PLEX+unsupported apps