I was once bumped in SQ paid F class although I could have easily reached the gate of my connecting flight and was traveling HBO.

But I fully understand and accept the rationale.

With the great number of daily occurrences, they cannot study each case individually when a flight is expected to land below MCT. They are not going to wait once you disembark to check if each connecting flight might be unexpected delayed. Some airlines hold a connecting flight for a few minutes if a large number of pax are affected, but that can trigger a cascade of delays. In any case, all these decisions are taken before the incoming ac has landed.
There are also some potential legal issues regarding including the pax list forwarded to some countries before the flight is allowed to takeoff.