I knew this thread was coming and the arguments read pretty much as I expected. Ultimately this comes down to a couple of issues.

If an option is provided - regardless of whether they know what they are doing people will try it. Go look at the red pill threads and check out how many "What is this?" and "I enabled it and now what do I do" posts. Its all very well saying they SHOULDNT use it - but a good percentage of the population will also push a button marked DO NOT PUSH.
By removing the option Nokia has at least raised the knowledge level required to install debs manually to "Knows what xterm is and command line"+"Needs root access and understands how to get it"+"Has an understanding of dpkg or apt". By doing so the number of people willing to undertake the process is cut drastically and the resultant "I SCREWED UP MY PHONE" threads are directly reduced. If the user REALLY wants to get the app installed then they at least are forced to learn something about the system and the risks involved. Pressing a button and installing is considered by many people "safe"

Now to the argument that "I need red pill because I dont want to open the keyboard" That is IMHO a total cop out. I guarantee I can open an xterm and install an app while you are still waiting for red pill to enable, anyone even remotely proficient with the command line could, if you cant - see above.

Personally I am glad to see red pill gone, anything that cuts down on "HELLLLPPPP MEEE" threads can only be a good thing. Now if they would just implement some sort of proficiency test you have to pass before you can get access to extras-devel I would be a happy man.