Is this breadth of topics common for the American higher educational system or did the author go to a special university?
This breadth is typical of the very largest universities in the U.S.
The number is further reduced by the fact that many of them are the same class with special qualifications to ensure placements. For example intro classes for designated transfer students. So you have the same class but 10 seats or something are only available to certain transfer program students.
The real number looks like somewhere in the ~400-600 range. Which is still very impressive but 3500 different intro subjects would be wildly excessive.
Related to the broader catalogue, I had fun in my Riflery and Table Tennis classes in college.
It requires all the following courses:
CEM 482 Science and Technology of Wine Production 3
CHE 483 Brewing and Distilled Beverage Technology 3
FSC 481 Fermented BeveragesWhile the value of some of these courses is somewhat questionable on their own (hence the old joke about majoring in "Underwater Basket Weaving"), they make a bit more sense as part of a broader program and/or a double-major.
For instance, you might double major in Chemistry, plus Food Science and Nutrition, if you intend to do some work in that industry - or perhaps Business plus Food Science and Nutrition.
Someone with less ambitious college plans might major in Food Science and Nutrition alone and aim for a job as a nutritionist, or a restaurant manager, etc.?
It's also common for people to register for courses like this as a fun or lightweight diversion from "more serious" majors. For instance, MIT offers a course on glassblowing, which counts toward the humanities & arts part of the general curriculum requirements.