It is saying that those claiming to have 'converted' to GMOs based on objective truth should not be taken at face value. Instead it is taking a class-based perspective to see (us) as middle class intellectuals seeking to use science to bolster our class positions.
They do not accept that "science" is a thing - they see it as a social construct which replicates particular power relations in society. As they put it, "heteromasculinized and whitened forms of power". In other words, science is a form of power domination.
This is actually fairly standard social science critique - very post-modern, pretty much what Vandana Shiva says. Basically we (the pro-science people) are useful idiots for the big agro-chem corporations whose interests we serve either knowingly or unknowingly.
Also as middle class intellectuals we like to see ourselves as rational and moral, so the authors grudgingly admit the effectiveness of our narrative of scientific consensus - liberals don't want to be anti-science, and they don't want to think of themselves hurting the poor.
So I actually take the paper as confirmation that our attempts to reframe the GMO discourse have actually been quite successful and gained traction - even among liberal bastions like Daily Show and NYT.
Hope this helps. This is the first time my entire university education (in humanities) has proven useful in the last 20 years :)
