This may be adequate advice for ill-prepared students, but is it universally good advice?
First, many students have a home life not conductive to study, or outright hostile. Traditional four year college provides a place where most things taken care of so you can focus on your studies. There are often enormous opportunities to find new friends that are much closer to your mental capabilities and career aspirations.
Second, universities have a wealth of opportunities that a community college simply lacks. For those who are motivated, there is research in all fields, which a student can help with. There are all sorts of work study programs, etc. If you're after work experience relevant to one's career, or a way to explore various careers, a university is really hard to beat. However, just because there is opportunity, does not mean every student is prepared. Professors want prepared students.
Third, most state universities have smaller class sizes for their honor students. If you are not honors student, it still is not hard to find out which paths are less full. For example, a 100 level socioscience survey that fulfills one's core requisite for computer science might also be filled with a 200 level class (having no prereq) in a more specialized class, such as pre-hispanic mesoamérica. You may have to work harder, but you'll also learn more.
Finally, doors of most professors are open. You just have to step though it. This personalized attention and direction are crucial to education. Most students simply do not know to do this, and hence miss the most important aspect of the process. Professors love to help when they meet a student who is driven to learn. By the time you graduate, you should have a half dozen professors who know you well enough that they will write a letter of recommendation. Those personalizes letters are
the ticket that open doors, to grants, further study, or to their professional colleagues in industry.