The problem is that a lot of writing from ancient sources e.g. Bible, Confucius etc. get discounted because of the language used. If you actually think about what they actually meant at the time a lot of the time there is a lot of wisdom in it but because of the language used it is too dense for most modern readers.
Unfortunately a lot of atheists just decided they knew everything once they realised that the Bible wasn't the literal truth. Many Christians wouldn't claim that and Atheists tend to point at the likes of Ken Ham to strawman the rest of the Christianity.
However I do appreciate Christianity in Europe is very different than it is in the USA.
Sadly I think a number of atheists decided that an absence of religion meant that there was also an absence of morality, at least in any universal sense. Oddly that put them in agreement with the theists, even if neither realized it.
One of the benefits of religion as I see it is an establishment of a morality that rises above "that which is popular in the moment." Most people are too busy dealing with the minutiae of day-to-day living to sit back and ponder the philosophy of morality, and while some religions may hold unpalatable beliefs they at least have the virtue of being predictable as opposed to the temporary vagaries of the mob.
