A very interesting point and one that's kind of been on my mind lately, more specifically with regard to obtuse academic writing.
On a less relevant note I followed one of the links to a page about 'interpretive labour' and from there to this Tumblr post about the habitual be in African-American English: http://theunitofcaring.tumblr.com/post/120069621981/theres-a-frequently-misunderstood-construction .
I was thinking to myself that it sounded similar to something we have here in Ireland when I noticed they do mention it's present in 'Gaelic'. (Note that the Irish language is called Gaeilge, so though it's often referred to as Gaelic, to us that sounds like saying an English person speaks Anglo-Saxon.)
Anyway this construction is indeed present in Gaeilge in a slightly different form. Tá mé ag snámh means 'I am swimming [now]' whereas Bíonn mé ag snámh would refer to the habitual habit of swimming. Tá and bíonn are conjugates respectively of the present indicative and habitual present (we also have a habitual past tense but I suck at remembering it).
The construction made its way into Hiberno-English, but rather than be we use do, e.g. 'I do be swimming' or 'he does be swimming'.