It would depend on the atheist I guess. However, since I do not know any atheists nor have I ever met someone who told me that they were an atheist, I am beginning to believe they do not exist.
Never?
Well, I assure you,
most of the people I know are atheists or, at best, agnostics (on the average, though, I prefer atheists). I am a young computer scientist; our field has always been dominated by materialist determinism and, thus, rabid atheism. Rest assured that they exist!
Now, to answer the OP: the question is, as others have said, impossible to answer, because every Catholic reacts differently to every atheist. Our Church’s official position is that freedom of religion, including atheism, is a fundamental human right, and, furthermore, that a person can honestly hold the position. (A pretty large portion of Protestantism disagrees. They believe that anyone who isn’t Christian is being
deliberately ignorant, and therefore evil. That’s where you get people using names like “the devil’s children.” Some of that’s leaked into Catholicism.) Rome also teaches that atheism is a fundamentally flawed position, whose errors can be illuminated by human reason, and that right reason in an honest intellect will ineveitably be drawn back to Catholicism as it learns new things and engages new philosophical ideas. It teaches that there are honest atheists, who have arrived at atheism (for now) through serious intellectual engagement, and they’re okay dudes (though atheism may lead them down very dangerous paths). It also teaches that there are
dishonest atheists, who rejected God for selfish reasons and are just trying to convince themselves He doesn’t exist even though deep down they know He does. Dishonest atheists are committing a serious sin. And it teaches that there are many atheists who never really engaged the ideas, who either left the Church out of anger against individuals (“I might have been a Christian if I hadn’t known so many.” --Gandhi) or against institutions that failed (people who left over the sex abuse scandal), or simply because they grew up in a secularizing culture and were never taught
one good reason why they should believe that any of this Church stuff is true (95% of young people who leave Catholicism fall into this category). This last group is somewhat responsible for their atheism, but there are also a lot of
other people–other Christians, who should have been living the Gospel and teaching the Truth and failed–who are responsible for it.
So the official stance is a nuanced one.
Personally, many of my friends don’t believe in God. I find the reasons they give inane, but, then, most of them have gone to Catholic school for fifteen years and never learned a gorram
thing about why Catholics believe what they believe. So how can I blame them for leaving what–to them–looks irrational? Anyhow, they’re nice people, and I find it much easier to get along with an atheist, who typically believes in reason, than an average Protestant, who typically believes either in
sola scriptura (if evangelical), or, worse, “faith for faith’s sake” or “the power of love” or some other crud like that that basically boils down to, “I believe whatever makes me feel good! Wheeeee!” (if mainline).
However, I have also found that a lot of jerks become atheists as a way to annoy their parents. So there are a
lot of hugely obnxious people out there who shout at me about how stupid I am for believing in religion, which would be laughable (because the loudest, most arrogant atheists usually have the most fatuous arguments, and yes I’m looking at you Mr. Dawkins), if they weren’t so incredibly
annoying.
The
worst is when one of those loser atheists end up in a locked room with a
sola scriptura Protestant. The atheist is determined to provoke the Protestant and usually pulls it off–not through argument, but just by being a jerk. The Protestant retaliates with Scripture quotes, and we’re off to the races. I hate that. A lot.
So, long story short, I like some atheists and despise others. Pretty much how I view everybody.