I think various wildlife control policies are an apt analogy. Out-of-support Ubuntu systems (or Windows XP or any other distribution) are vermin in that they are responsible for spreading disease. All their applications fall behind in support and they get hacked with ridiculous ease. They're then used to hack other machines, send spam, host horrible crap. Hacked and exploited machines form the basis of internet crime.
If you want to keep a wild rat, you can. If it bites you, that's your fault. But as people are here to help people with their pet Ubuntu installations, so why should we or any other SEsite seek to facilitate anything but the swift and humane dispatch of your 11.10 box that hasn't received an update in almost 18 months?
Your choice (or more that a number of people makingPeople are free to make the same choice) to stick with something that actively makes the internet worse but they shouldn't expect our blessing through community support.
I do get the other side of this, and you've done a good job at enumerating many of the problems of keeping the policy. I'll add that we occasionally get caught up in huge bouts of nonsense as historical questions get sucked into the review process... But the public health argument is pretty serious.