Gary DeMar must be a bitter and small minded man if he feels the need to ceaselessly harp on this topic. DeMar has his own bizarre interpretation of the end times that is perhaps even more out of step than Harold Camping.
As for Harold Camping, we shouldn’t be surprised that the adversary would push him and other to unbiblical extremes - for the very purpose of smearing the truth with a “guilt by association” argument. In the 1st century, Paul’s gospel of grace was mimicked as “sin as you please”.
The fundamentalist lust to predict the future is the canary under the carpet, the problem that just won't go away, no matter how many careers are wrecked and lives are short-changed by those who proclaim as absolute truth the notion that God has already decided to take a dive.