We atheists are all too familiar with Christians who dismiss any of the contradictions we point to in their "holy" book, making it clear that they are going to continue to believe in biblical inerrancy regardless of how poorly it corresponds to external reality. It doesn't matter that science has demonstrated that the Earth is older than 6,000 years; if that's what they think their book says, they'll believe it. We've all had countless experiences of asking Christians questions they cannot answer coherently, only to have them say that they are going to keep believing based on faith. Some almost seem to think that we will be impressed by this.
It is worth remembering that one does not need to be a Christian or any other sort of religious believer to decide that one does not particularly care what is true. Many people, including some atheists, are perfectly willing to set truth aside if it gets in the way of things they consider to be more important. We could pick almost any topic we wanted and find evidence of this, but let's select an especially easy one with which anyone reading this will be able to relate: politics.
If you spend any time on social media, you've seen people promoting politically-relevant content that you have recognized as blatantly false or highly misleading. Some of the time, the person promoting it probably doesn't know that it is false. But other times, the content in question has been so widely debunked that it really ought to remind one of some of what many Christians do with their bibles. In these cases, the person promoting the content probably knows it is false but is promoting it anyway. Why? They are doing so in service to something they value more than the truth.
Suppose that you really like a particular Democratic candidate. You want this person to end up on the primary ballot and ultimately become the party's nominee; however, they are not polling very well. What's even worse is that a candidate you despise is polling ahead of them and seems to be attracting voters your candidate might otherwise have. Almost any of us in your situation would want to bring down the hated candidate and elevate the one we liked. If one were to decide that the ends justified the means, one might push false or even thoroughly discredited stories if one thought they would help.
I have a very difficult time imagining that most reasonable people would seize on something an old politician did or said 20+ years ago and try to use it to impugn his or her character today. On the other hand, if they believe that the stakes are sufficiently high that the ends justify the means, then we should not be surprised to see this. In fact, we should not be surprised to see an even worse version of this where old stories that were previously discredited are presented as if they are accurate. Whether they are true or not somehow becomes less important than whether they might be effective in accomplishing our aim.
Why was the "fake news" used by Russian trolls to undermine the 2016 U.S. presidential election was so effective? It was so effective because many Americans didn't particularly care whether it was true. As long as it reflected what they wanted to be true, they were happy to do their part in spreading it. This isn't all that different from the Christian who tells you that they aren't terribly worried about the truth of what they believe because it makes them feel good to believe it.
I saw some atheists promoting old and discredited stories about various Democratic candidates on Facebook recently. My initial reaction was one of surprise, but I reminded myself that some atheists are not skeptics, humanists, or even particularly reasonable people. Being an atheist does not necessarily mean that one will value truth more than anybody else does or that one is somehow above peddling discredited stories to promote one's preferred narrative. Perhaps the atheists who are willing to do this should at least be a bit kinder to religious believers if they want to avoid accusations of hypocrisy.
