"atheists and agnostics think of themselves as more open-minded than those of a religious bent, but are actually less tolerant to differing opinions and ideas" - venus
When you believe in and preach bollocks it is harder to be intolerant to other bollocks because the same arguments you would use against their bollocks would also apply to yours. Therefore it is better to tolerate another's bollocks lest attention is drawn to your own...
Atheists and agnostics on the other hand don't have to worry about defending bollocks and are therefore in a better position to call the bollocks believer to account.
Also, I think a stone age man would probably also tell you to fuck off, as I doubt they were dumb enough to accept your nonsense...