Some religious people claim that atheism, which is defined as a lack of belief in deity or deities, is inherently nihilistic. Since atheists come from all nationalities, races, socio-economic backgrounds, and indeed all walks of life, it is reasonable to say that making such a sweeping generalization of all atheists isn’t fair.
However, many atheists spend an inordinate amount of time criticizing religion. Visit any atheist blog on the internet, and there you won’t find one positive article on faith. It seems like everything they post is hostile towards religion. You’ll never see them post a link to a news story about Christians feeding the poor or being good people in general. The same can be said about atheist books: read any book from renowned atheists such as Richard Dawkins or Sam Harris, and all they have to say about religion is bad. In fact, the world's most famous blasphemy advocate Christopher Hitchens even wrote a book called How Religion Poisons Everything.
Since it seems like almost all atheists are hostile towards religion, particularly Christianity, which is an inherently peaceful faith that improves morals and provides eternal salvation for all believers, wouldn’t it make sense to think that atheism is inherently nihilistic? It’s not like you ever see atheists praising religion and talking about how good it is. If that is what they believed, they probably wouldn’t be atheists in the first place.