Enterprise relies on companies such as RedHat and Oracle to some extent in lieu of conducting code analysis and to certain types of security testing.
It would be rather surprising if they were not at least approached by Federal agencies such as NSA and FBI.
To put it another way, because Microsoft has a closed source model, the intelligence agencies took the approach described in the article. From that, it may be a mistake to conclude that the strategy pursued with Microsoft was the only strategy pursued. It just happens to be one that would pass across the desk of an analyst, rather than someone on the operations side.
Viewed as an intelligence operation, it would be grossly unprofessional of such agencies not to have placed moles within the open source community, or for those moles to be seen as highly skilled contributors on open source projects. The three letter agencies have decades of experience infiltrating both commercial organizations and those motivated by something other than money.
I suspect it is easier to turn an open source hacker than a diplomat - not just ideologically but because the open source community lacks a state funded organized counter-intelligence apperatus.