Not necessarily true. The CS courses required for a CS major at a school where the CS major is good may take up about 25-40% of the total courses or credits needed for a bachelor’s degree. This leaves a lot of schedule space for other degree requirements (e.g. math courses, science courses for engineering-based CS majors, humanities and social studies breadth courses) and free electives. Of course, degree programs with larger numbers of other degree requirements will have fewer free electives. For example, MIT students will need to use about a fourth of their courses on math and science general education requirements, and another fourth on humanities, arts, and social studies, while Brown students do not have any of these types of requirements.
It is true that CS courses with programming assignments and projects tend to be high workload courses compared to others of the same credit value.