Humanism

[Pyrrho]

That is certainly true mh that calling yourself a humanist does not carry with a stigma like most other isms. But the point Professor Gray is making is that it is not logically consistent to hold to humanism and a strict naturalistic or secular worldview. Humanism is injecting properties that are non-existent in such a framework which is why he identifies it as the new religion of a post Christian Europe and parallels it to the ideas in Christianity.

Humanism is combining an ethical view with (in the case of secular humanists at least) atheism.  That would be logically inconsistent if ethics and atheism were inconsistent, but they are not.  It may, however, not be consistent with your view of what ethics is.  But that does not make their position inconsistent.

Broadly speaking, it is the view that is and has emerged from the Enlightenment.  Broadly speaking, of course.

Here is wikipedia's introductory paragraph to "humanism":

Humanism
From Wikipedia, the free encyclopedia

Humanism is a philosophical and ethical stance that emphasizes the value and agency of human beings, individually and collectively, and generally prefers critical thinking and evidence (rationalism, empiricism) over established doctrine or faith (fideism). The meaning of the term humanism has fluctuated, according to the successive intellectual movements which have identified with it.[1] Generally, however, humanism refers to a perspective that affirms some notion of human freedom and progress. In modern times, humanist movements are typically aligned with secularism, and today "Humanism" typically refers to a non-theistic life stance centred on human agency, and looking to science instead of religious dogma in order to understand the world.[2]

https://en.wikipedia.org/wiki/Humanism