Why do many atheists use the term atheist when the meaning they use is agnostic?

I used to be Agnostic so I know the definition of what Agnosticism means. I'm Atheist now and believe me I know the difference between the two terms. But I have realized that many Atheists here aren't particularly Atheists, they are just angry with religion especially Christianity. But they like to call themselves spiritual and praised Eastern religions like Taoism or Buddhism. I don't understand what is their reasoning. But I'm not like them.