Difficult to say, after all folk here are wishing to bar someone who has yet to break the law in this country, and even the report seems to imply she is abusing when her claim is that she merely identifies those who she believes are possessed. Exactly what is the dividing line between barring or allowing someone who seems not to have been prosecuted for anything anywhere ?
For sure we need no one encouraging this victimisation of children here, even if done in good faith, for if it leads to abuse and murder then it transcends any acceptable level of religious tolerance: but with just the fear of what might be, the authorities probably found it difficult to justify a ban. Perhaps being barred from preaching this might be an alternative.
Of course long term one needs to persuade the population of countries such as Nigeria that one need not fear a spiritual world and that this sort of act is simply irrational, not unavoidable, as many there presumably believe.