If you found yourself in a theater and after fifteen minutes found that the movie was so disturbing as to be nauseating, would you keep watching or leave the theater? And when you spoke of it to others, would your opinion not be merely of those first fifteen minutes? But since you didn't watch the whole movie, does that mean your opinion of what you did watch is invalid?
Of course not.
I have read plenty of parts of the Bible. The parts that I have read have wavered between inspired and disgusting, and the ones that America's common evangelical Christian perfers are the largely disgusting ones.
So, yeah, I haven't read the whole thing.
But that hardly disqualifies me from commenting on the parts that I have read.
And it especially does not disqualify me from commenting on all the BS I've endured listening to and trying to understand Christianity.