Oh, I don't disagree; some topics are inherently intractable. It's just that, in all my experiences, the numbers are more like 1 truly intractable topic for every thousand that some expert will mistakenly claim is intractable simply because they haven't put the effort into tracing out the connections to other topics.

The woman top row of this xkcd pretty much sums up my life:

http://xkcd.com/566/