Recently, this CNA (Channel News Asia) video is very popular on YouTube. Do check it out. Basically, due to the segregated nature of the education system, GEP, IP (Integrated Programme), Express, Normal Academic and Technical students rarely mix with each other, if at all. Hence, there may be some prejudices and biased views from each side towards the other.
A more in depth official commentary can be found here: https://www.channelnewsasia.com/news/cnainsider/regardless-class-race-religion-survey-singapore-income-divide-10774682
In light of this, the story of From PSLE 124 to PhD A*Star Researcher is very remarkable, on how a student overcame prejudices from society to reach his full potential. Do read it if you haven’t.