It was mostly about the perception that people with a bachelor's degree had not learned anything useful yet.
There is a lot of variation between countries, but European countries often have a dual-track system in higher education. You can choose between the academic track (universities) and the vocational track, with more people ending up in the vocational track. Some fields are available in the academic track, some in the vocational track, and some in both. Professional fields such as healthcare, business, and engineering are often available in both, with the tracks preparing for different roles in the field (such as nurse vs. doctor).
Imagine being used to an educational system with two kinds of degrees. Some indicate practical studies preparing for a job, while others tell of longer theoretical studies and specialization. Suddenly the system changes and you start seeing a third kind of a degree: shorter theoretical studies without going particularly deep in anything. What use do you have for people like that?