Once again, a post with a dubious argumentation.
You haven't provided any evidence that Generation Lab is not a reliable polling organisation.
The sample is representative of the young population, which means It's not only composed of students.
Actually, their sample is more reliable as it is only composed of young people (804), while they represent only a part of the Quinnipiac University sample which is about the whole population (1257 for the whole population)). In short, they have surveyed more young people than Quinnipiac University.
Note that I did not claim that Quinipiac University was not reliable. I wrote that Fox News selected this particular poll.
Poll results may vary according to their methodology, their sample, etc... That's why no conclusion can definitely be drawn from only one poll.