I think the author may have a conservative bias. For example, he writes: "The proposal died in part because of liberal opposition to a work requirement and obstruction by a well-organized welfare lobby, Moynihan would later write." If it's got a work requirement it's not really minimum income, is it? It certainly doesn't have the same properties as one - far from reducing bureaucracy, the proposal in question would've created a whole new bureaucracy around making sure people were working or seeking work and penalizing them if the bureaucrats decided they weren't trying hard enough. Oh, and it was specifically aimed at replacing welfare for single moms at a time of massive unemployment.

Basically, the reason he sees Basic Income as something of particular interest to conservatives is that he's hijacking the term to describe conservative policies of trying to punish people into work regardless of how realistic it is for them to find a job.