Hi Monnkai, atheists (non-Christians in general) cannot understand the Bible (from God's POV anyway), and they see what it has to say as nothing more than foolishness.
.........1 Corinthians 2
.........14 ..A natural man does not accept the things of the Spirit of God, for they are foolishness to him; and he cannot understand them,
.........because they are spiritually appraised.
Considering this, I'm sure you can understand why a non-Christian/
natural man or woman might think the Bible is poorly written.
~Deut
p.s. - the closest thing I have ever seen to a non-Christian understanding the Bible is a rabbi friend of mine. Oddly (for a conservative rabbi), he did his dissertation on the Gospel of John, and he ended up knowing and understanding what it said as well or better than any Christian pastor or theologian I've ever known. Unfortunately, while he understands the words of the Gospel as a Christian would, his problem is that he can't bring himself to believe that any of it is true