I hesitate to draw the conclusion that the majority of Singaporeans do not want TT as their president. This is akin to holding a contest amongst friends for the most-loved person and concluding that the losers are hated.
The information provided by a FPTP vote is binary in nature. Each vote only tells us who a candidate most prefers, and nothing else. Perhaps he approves of all or some of the other candidates, just slightly less. Perhaps he disapproves of everyone, but he hates his choice the least. But such important information is destroyed and irrecoverable with a FPTP system.
My preference is for approval or Condorcet voting.