For any atheists who might be reading this post, the title is a name that you probably try to avoid. A militant atheist is someone who tries to push his own disbelief in a deity on other people. I personally hear the term thrown around a lot, and it seems that it is of the opinion of most people that these militant atheists are as bad as a fundamentalist Christian.
It is a rude act to attempt to change someone's opinion on religion, whether it is to change it from one faith to another, to change it from disbelief to belief, or vice versa. I am here to tell you that this rude act is a necessary one in this instance, as religion is a plague upon humanity and science. If we lived in a society where only certain people could vote, or only a small council of people made decisions for us, these people would be fine living in their ignorance, but sadly we live in one where everyone can vote or voice their opinion on an issue, influencing it in their own way. In such a society, we need to try our best to rid every ounce of ignorance in our populace. A very large source of this ignorance is religion, and in the United States it is Christianity, Mormonism, Judaism and Islam.
These religions convince people that homosexuality is wrong, that certain fields of science are wrong, and hold society back in general. They oppose things such as stem cell research, abortion, and marriage rights for homosexuals, for no good reason other than that their parents and preacher told them to and they never questioned it. For those of us who have transcended that state, there is no reason that we shouldn't try to help others see the rational side of arguments. It is not the people you should hate for "being stupid" and believing, it is the idea that they follow you should hate. There is nothing wrong with hating an idea and making others question it. We can only bring more understanding and enlightenment into our society by doing so.
You may be "stooping to the level of fundamentalists" by asking other to question their own beliefs, and you may become disliked by some, but you will still be aiding humanity. The faster everyone adapts to our most current scientific theories, the faster our society can advance. Passive methods are not very effective.
So you should not fear the title of "militant atheist". The next time the subject of religion arises with someone you know to be religious, you should simply ask them to explain to you why they believe, and if they have ever questioned their belief. Perhaps point out some flaws in their logic, but aggressive arguments on this topic tend to make them defensive and extremely close-minded. Just get them to question their own beliefs in a logical fashion, and their own internal battle has begun.