This is one of the more salient clues that this article was written by someone squinting through a film of pro-religious bias. Dawkins and Harris go to extravagant lengths to avoid inaccurate generalizations about religious people, particularly in their published work. Did this guy think his audience would appreciate being insulted with such amateurish spin doctoring? Impartiality may be beyond him, but honesty shouldn't be too much to ask of a columnist for a mainstream newspaper.
As for the research itself, religion may well make people who live in developed countries "nicer." It's not exactly a revelation that places that aren't beset by scarcity and social instability are less likely to summon up the caustic provincial tribalism that bubbles away in the core of our most influential religious traditions. (I'm assuming the people interviewed weren't selected from one of the innumerable places in Africa or the Middle East where gangs of pious brutes will gladly shatter your face if you seem like you belong to the wrong sect.)
We'd all do well to remember that the appearance of goodness is an inconsistent indicator of actual virtue. Niceness, in any case, is a tertiary virtue, and easily faked with hypocritical acts of charity. There are superior qualities that I value in others and strive to cultivate in myself. The capacity for self-criticism, for instance. Pragmatism. Compassion. Loyalty. Curiosity. Self-respect. Confidence. Tolerance. Open-mindedness. I don't care how nicely you behave: if you deliberately frighten or stultify or lie to children, promote or engage in flatfooted and uncritical opposition to science, or believe that being of a certain race, gender, creed, or sexual orientation weakens another human's claim to the same rights you would claim for yourself, you have more important things to do than maintaining a wholesome appearance. Work instead toward being more rational and decent in daily life.