I think it is true many atheists will happily offer arguments for their beliefs, as will theists. Some atheist arguments are very powerful (for example those of David Hume) while others are less convincing. Some atheists are also ‘missionaries’ in the sense they believe only their belief is true and rationally justified, while many theists are also missionaries in the sense they believe only their belief is true and rationally justified. In addition to this of course for the theist, the argument is not just about a rational belief but also about saving someone’s soul.
Atheism and theism are positions one can adopt (and many thinkers through history have adopted both). I’ve seen very clever arguments from theists and many from atheists, but in the end it is an existential decision based both on one’s ‘faith’ (in the sense of what one accepts without always demanding an exact rational demonstration) and reason, and often also emotional factors as well, as to what position one adopts on ultimate questions.
