"Humanism/ist" means different things in different contexts. I basically agree with conceptions of it that I'm hearing here, but I also hear the term used disparagingly, and in ways that I also agree with.
Those I hear accused of being humanist in this sense are those who argue, for instance, that we all have some certain sense of right or wrong, or that we all basically have the same emotions, or that we all experience love or hate or the "need" for revenge in basically the same ways.
To me, "humanism" is often used to describe beliefs in supposedly essential human qualities and attributes, at the expense of attention to and understanding of how experience is always filtered through and shaped by social filters and constructs. A problem that then arises is when people in positions of power (often unwittingly so) assume that their modes of experience are universal, instead of just another kind of, or set of, experiences. They then often proceed (being empowered) to impose, or try to impose, their ways on others.