Sometimes it seems to be. Militant atheists seem to be pretty ideological, to say nothing of evangelical.
It's defined as the lack of religiousity. If you deny that the term anti-theist is a real or non politicised word then feel free to create another one.
I have a tendency to equate 'atheist' and 'anti-theist' and tend to think of the two as synonyms.
My reason for doing that is because on internet discussion boards at any rate (places that oftentimes don't have very much resemblance to real life), self-avowed 'atheists' typically
are anti-theists.
They aren't people uninterested in, neutral about, or with no views on religion. Internet-'atheists' seem to be obsessed by 'religion' (typically treating that word as if it was synonymous with biblicist protestant Christianity) and passionately and viscerally hostile towards the whole subject. Atheists will announce God's non-existence at the drop of a hat, just as freely and just as aggressively as evangelical missionaries announce that Christ is lord.
I don't really understand why you want to deny something factual. Every dictionary will tell you that atheism means non religious, nothing else.
Dictionaries aren't the best arbitors of philosophical discussions, and most discussions about the meaning and extension of words and concepts turn into philosophical discussions if you push very hard on them.
My own tendency is to divide up your non-religious category into several sub-groups.
There are people with no knowledge of or opinions about religion. For adults of normal intelligence that's probably rare, but babies belong in this category. I don't really consider infants default atheists.
There are people who do know about religion and simply don't care about it one way or the other. It's a fairly diverse group. Some of them explicitly don't believe in "God", others are nominal religious believers, others believe in some vaguely defined "higher power" and leave it at that. That, by the way, is why it's misleading to interpret religious adherence figures as if they were statistics about underlying religiosity. Plenty of Irish and Italian Americans will tell pollsters that they are "Catholic", despite their not having been inside a church for decades. The label is part of their ancestral identity. I'd be inclined to call this whole class 'secular individuals'. Their interests are directed towards the matters of this world. But not all of them would agree that they are 'atheists'.
There are also people who are very interested in religion and for whom religion plays a big part in their lives. But they aren't believers in any particular religious tradition. They don't believe in the Bible or its Yahweh, and they don't believe in Vishnu or Shiva. But nevertheless, they feel what they interpret as the presence of a "higher power", sometimes very strongly. You encounter people like this in the more avant-garde spiritual bookstores. I guess that I'd call these people 'seekers'. Most of these people would probably deny that they are atheists, despite their not being conventional theists.
And there's another group that knows something about religion, quite a bit in some cases. What's more, they know that they don't believe in it, don't like it one bit, and would be very happy to see religion dissappear entirely. Some of these people can become just as passionate and aroused about those opinions as pentecostals about the holy spirit. This is the grouping that I tend to think of as the prototypical 'atheists'. They are the kind of people you find joining groups like American Atheists, reading Hitchens and Harris, and posting aggresively on internet discussion boards. My suspicion is that some of this group are former religious believers who may still harbor some bitterness towards the faith that failed, and in some cases shunned and rejected them.
There are other groupings of non-believers as well. One of them might be the 'academics', people who are fascinated by the phenomenon of religion for reasons of its historical, philosophical, psychological or anthropological interest, but oftentimes don't really believe in its literal truth themselves. A great deal of the academic literature on religion is generated by this kind of person. You can even find examples of this type among Christian theologians. It's probably the variety of non-religiosity that I personally gravitate towards.