A few thoughts on Humanism and Buddhism.

Humanism may be described as a way if life and as a philosophy, i.e., a conclusion, devoid of metaphysics, with regard to perceived truth and values by which one tries to live. The same may be said of Buddhism, except that it's not entirely devoid of metaphysics. That is perhaps is the main difference between Humanism and Buddhism (generally speaking). Humanism is simpler and less encumbered. It has no dependence upon historical events and artefacts, nor upon sacred texts, canonical or otherwise. Nowhere is there to be found the worship of a god or of divinities. All of these are to be found within the various forms of Buddhism, either in the theory or the practice. Buddhism has been prone to significant modification by the various cultures into which it has been introduced. Thus there many and diverse beliefs and practices throughout its domain. The practices are less consequential, and no doubt beneficial, since they are concerned with harmless ritual which probably serves several purposes such as recollection of the 'truth' and promotion of fellowship within the community. The beliefs however, although perhaps mostly innocuous, are inevitably divisive. One therefore finds Theravada Buddhism (The Lesser Vehicle) and many versions of Mahayana Buddhism (The Greater Vehicle) having mutually exclusive beliefs.

I should add that the eastern philosophy with which I can most identify is that held by the Dalai Lama who, quite typically, said that if there's any dispute between science and Buddhism, then science wins. Humanism, however, appears to have totally shed all the inherited paraphernalia of religion, and takes a fresh look at reality from a truly scientific, yet human, perspective.

As I said, those are just a few thoughts, and I would be interested to read the thoughts of anyone else on the comparison of Humanism with Buddhism.
"Time is what prevents everything from happening at once" - John Wheeler