I agree with you that the Left Behind series is not based in pure biblical truth but seems to be a mish-mash of bible prophesy and Tim LeHaye's imagination. Interesting but flawed and misleading if anyone accepts it as anything more than pure fiction.
The lead article criticizing the series seems to be another mismash of mistaken fears about Christianity and Christians in general, posing as some sort of literary/social comment. About as useful as the books it complains about.
As a Christian, I don't need to read fiction based on what other Christians' imaagine about The Last Days or anything else. I have God's Word, the Bible. While I respect Tim LaHaye, the Bible is good enough for me.