An ECG celebrant shares the general attitude of the eg:FAQ and promotes it in one way or another. No means to verify that the celebrant is an individual is implied - this is not a credential. Anyone may describe themselves as a celebrant. To do so avoids the scrutiny that ECG adherents apply to each other, i.e. ECG trolling. Celebrants need not be smug pro-trolling trolls but certainly a great many have been.
Few celebrants ever become ECG adherents - some have no real interest in the methods nor their results, and would not recognize whether they were "getting it" or not. Celebrants may actually scoff at the idea that any governance organization is required to regulate ethical trolls, e.g. they may be political anarchists. So the celebrant role, as in Kwanzaa, exists to accomodate people of very widely varying point of view, some of which may be incompatible with ECG direction for now. This too is good politics.