They believe this because there is honest disagreement among Biblical Scholars and each position has its own relative merits. I personally don’t ridicule any of the positions since I am not absolutely certain how it will play out. What I am certain of is that it is playing out.
I have major problems when people ridicule other Christians for honest disagreements over eschatology. You may not understand it, but please respect that people can and do differ in their reading of Revelation and the prophecy of the end times.
But just a few posts earlier you wrote:
How nice of him to take Scripture out of context and develop a premise that isn’t supportable by the Bible.
If people can honestly disagree over eschatology, who are you to say that he’s taking anything out of context? Best you can say is that he’s taking Scripture out of YOUR interpretation of the context.