This FYC-as-general-academic-literacy-inoculation encourages students to view reading as just another requirement, rather than as an opportunity for discovery and an important form of knowledge making. Take, for example, the research paper, a staple in this model of FYC. All too often, this assignment has no audience other than the teacher, no purpose beyond earning a grade, leaving students with little motivation to locate quality sources and use them thoughtfully.
With limited types of writing and the teacher as the audience, it sucks the life out of the writing and allows for little individuality. Very likely, students learning to tailor their writings for a specific teacher may help in the future for writing for specific people, but not for sharing with a group at all.
I think it is more of an assumption for them to mention that there is little motivation to locate quality sources; it really depends on whether a teacher will look at the resources used. This might just be my bias because I have needed to use quality resources resources for multiple papers on things I'm not interested in or I was just motivated enough to get my A, all because I knew my instructor might or is looking for it.