Groupthink and forced consensus is rife within the PAP.
Also, Lee Hsien Loong has 'royal blood' within him, and his wife holds the key to the nation's coffers. Best not to get on the wrong side of them and jeopardise your own career within the PAP.
Singapore's political system is such a farce. In other countries, there would have been at least a censure motion or a no-confidence motion against Lee Hsien Loong.