Although atheists claim to be opposed to all religions, it makes no sense for an atheist to say "religion says this" or "religion has done that". The word "religion" is a very broad term, much like the word "animal". The word "animal" encompasses a wide array of weird and wonderful creatures. There are very few things you can say about any animal that will encompass all animals.
In today's image, I have randomly chosen 3 animals: The emu, the cuckoo wrasse, and the lion. Is it wise to say "animals stand on two legs"? No. The emu does, but the lion has 4 legs, and the fish has none. Does it make sense to say "wild animals hunt zebra"? Certainly not. While wild lions may hunt zebra, emus don't even live on the same continent, and Cuckoo wrasse can't run fast enough, among... other problems. Can it be legitimately said that animals breathe under water? Not at all. The cuckoo wrasse needs to live underwater, but while lions and emus can swim, they need to resurface for air.
In the same way, it is all but impossible to paint all religions with the same brush. A religion, simply put, is "a set of beliefs concerning the cause, nature, and purpose of the universe". Just as the definition of animal encompasses a wide range of creatures, making it almost impossible to encompass all animals by describing an attribute of one, so also are there few attributes of any religion that can be applied to all of them.
This actually includes the existence of God. There are many atheistic religions. Evolution, Buddhism, Jainism, just to name a few. This is where many people get tripped up. Some people call atheism a religion, which it is not. Rather, atheism is a religious orientation. To go back to the animal comparison, one could say atheism is a level of religious classification, just as mammalia is a class of animal.
In other words, atheists cannot even say "religion says there is a god", because it actually doesn't require a god. It needs beliefs about the cause, nature, and purpose of the universe. But we all have those. In fact, I even had one atheist quote Gandhi at me: "There are as many religions as there are people". And in a way, he's right. No two people have identical understandings of the universe. In fact, atheists have such radically different understandings of atheism, they often contradict each other. Is it fair for me to say "atheism says there is no such thing as the supernatural"? Some atheists reject all supernatural claims, some atheists believe in ghosts and magic, even demons. The only claim an atheist needs to reject is "at least one god exists". Beyond that, they're free to believe whatever they want. In fact, beyond all imagination, an atheist can technically believe Jesus rose from the dead!
All of this means that an atheist's claim to reject all religion is false, and their reasoning for making it is ultimately fallacious. Not only do atheists have some form of religion, whether they like it or not, but their reasoning for rejecting what they call "religion" makes as much sense as saying dogs don't make good pets because animals are too big to fit through the front door.
Of course, not all atheists understand this. Most people don't think through their worldview until they are challenged to defend it, and so the fallacy of painting all religions with the same brush never occurs to many atheists until it's waved in front of them. But for some atheists, especially the kind you'll find online, there is a deeper motive. See, Christianity is a very strong religion. There is a lot of evidence for Christianity, and very few compelling arguments against it. But this isn't the case with every religion. In fact, there are even some very silly religions that pretend they are Christianity. Atheists must paint Christianity with the same brush because when you isolate Christianity, it becomes nigh impossible to even stay afloat. Even many amateur apologists, armed with only the most basic arguments, can hold their own against an experienced atheist. Thus, it is essential for atheists to lump Christianity in with weaker religions.
The main strength of Christianity is its central pillar. Christianity stands or falls on the resurrection of Jesus Christ. If Jesus did not rise, Christianity is false, because it is our central message. But if Jesus did rise, it is essential that we trust Him, for one man who can walk out of His grave is more credible than billions who are heading to theirs.
The evidence that Jesus rose is all but insurmountable. In fact, it is so powerful that many atheists won't even try. Bart Ehrman, for example, advises his students not to try to come up with an alternative explanation. This is because the only explanation that makes sense of all the evidence that Ehrman himself admits exists is that Jesus rose. All other explanations fail to take into account vital pieces of evidence, or just stubbornly refuse to admit they exist. Some atheistic explanations are frankly insane, sometimes going as far as appealing to the existence of aliens.
There is no need for all these rescuing devices. If the evidence points to the resurrection, believe the resurrection, not only because it is true, but because it is the only way to be reconciled to God. Sin makes this impossible, but because Jesus died for our sin, all who confess Him as Lord and believe He rose from the dead will be saved. Yes, this is religion, but this is truth that atheism denies.