Over all, "Why a band of American heathens is fighting to protect atheists — and Christians — abroad", is a good piece. I am glad that it was produced. I also would like to state up front that of all media outlets focused on religion/philosophy Religious News Service does a pretty good job presenting the views of non-theists.
That said, even when RNS publishes generally positive pieces on atheists any number of myths and stereotypes do to some degree slip in. The headline does imply that it is unusual or surprising that non-believers would actually be interested in fighting for the rights of everyone. Why? Being an atheist does not automatically mean that you are also a humanist but it is fairly common. As a humanist I feel an obligation to look out for my fellow human beings regardless of any other trait or characteristics. Human/Civil rights should be universal. I find this approach and attitude to be rather standard among atheists.
To some degree I think the surprise stems from the false notions that atheists are immoral and/or apathetic. I would pose the rhetorical question; why wouldn't you fight for the rights of all?, to anyone who didn't find the headline odd or slightly misleading.