Yes. But not for the reasons you might be thinking of.

It is not the risk of offending strongly religious people that matters. They go around offending each other all the time anyway, way more than atheists could ever offend them. And frankly, they are just not commonplace enough in the circles in which atheists typically move to worry about.

It's the non-seriously-religious people you should consider. I'd say over 90% of people I interact with are either atheist or agnostic. Or they are just plain disinterested in religion.

This last kind of attitude shows up as conventional social religiosity along the lines of "yeah, sure, I believe in God/I am spiritual but not religious/I believe in a higher power." The sort of position you might come up with and accept if you've only spent about 5 somewhat drunk minutes on such thoughts in your entire life, and are mainly into religion for the social/community benefits. These are people who have pruned the more embarrassing kinds of silliness in literal religion, such as the world being created in 7 days in 4000 BC or whatever, and made the residual mysteries sufficiently abstract to be given a label like "spiritual" and hastily shoved away, never to be thought about again. I call these people "lazy thinkers." Their views simply cannot sustain more than 10 seconds of very dull conversation. At best they'll offer some tired borrowed line like "there are some things that are out of the domain of science."

A declaration of atheism hurts you most with this last category of lazy thinkers: ordinary people who are so casual about philosophical questions that they have no strong views at all. Among these sorts of people, taking the trouble to assert a strong religious position of ANY sort (and yes, a declaration of atheism is as strong an assertion of religiosity as a declaration that you are a devout, practicing Christian) is viewed as social fumble. Very gauche. Cultivated people do not talk about religion, paychecks or politics passionately in public. They stick to lighter topics. Atheism is viewed as a passionate position by default. Most people think there is no such thing as "casual atheism" comparable to their "casual religiosity."

Admitting you are an atheist reveals that you've actually thought more deeply about such things than is socially fashionable, and will hurt you the same way correcting someone about a dinosaur mistake will (a friend tells your kid, "Hey, your toy T-Rex is awesome" and you go "no, that's a velociraptor"). You really don't want to reveal that you've thought too much about God for exactly the same reason you don't want to reveal that you've thought a lot about velociraptors. Both mark you as a nerd. Religiosity and atheism are both nerdy preoccupations.

Real atheists, if they are socially competent, and hanging around with other socially-competent atheists and people who don't think about this stuff, don't need to talk about this stuff at all.

Around the religious, there is usually no point.

There is some intellectual value to thinking about atheism in an academic sense. It trains you to think about such interesting metaphysical questions as flying spaghetti monsters, Russel's teapot and the anthropic principle. But this can be done privately with the help of books/Wikipedia.

So there is no really good reason to ever talk about atheism. In a way "serious atheist" is an oxymoron, which ironically, contradicts the common view that the only kind of atheist is a serious one. To adopt atheism is to decide that religion is a sad delusion for the clueless, and to NOT take it seriously anymore. Dignifying religious beliefs by being too earnest about your non-belief, on an ongoing basis, kinda defeats the purpose. Once you've adopted the non-belief, there really isn't a whole lot there left to think about, except as an anthropologist-tourist among religious people.

I suppose there is a weak case to be made that atheists should get serious, socially vocal, and organized (as Richard Dawkins does), in order to combat the social ills of religion.

I happen to think that the social ills of religion are overstated, and that widespread atheism would not really change things much. We'd merely find that wars and other nasty things that we attribute today to religion would simply arise from other causes.

I suppose it goes without saying that I am an atheist. I suppose it is also clear that I don't particularly respect religion (though I am interested in it as an anthropological domain, which the religious don't really appreciate as the "right" kind of interest). I can respect religious people, but it is usually despite their religiosity, except in very rare cases where their religiosity takes on a very interesting form (Pascal and Kierkegaard come to mind).

I generally avoid religious conversations like the plague, but if a religious person forces me into a conversation, I am afraid I don't hide my contempt very well. Especially if they say something particularly shallow, like "I am not religious, but I am spiritual" (a position I consider a great deal less intellectually respectable than something like "I believe in the death and resurrection of Christ" which at least creates a fascinating, non-vacuous debate about historicism etc... I've had a few serious debates with strongly religious people, but I can't stand the earnestly "spiritual but not religious" crowd. They pretend that they have an interest in New Age stuff and mysticism, but are typically completely clueless or dumb about those subjects).