Harold Camping has been deservedly subject to ridicule because May 21, much like May 20 and May 22, was notably free from apocalypse. Sometimes, the best way to deal with heretics isn't to argue with them from Scripture, but instead to giggle at their arguments supposedly taken from Scripture. Nonetheless, I give the man credit for how he explained away this present age's stubborn refusal to come to an end: the judgment was "spiritual."
This explanation has some plausibility because most people, including most Christians, tend to think "spiritual" = "having nothing to do with real life." Hence, Christians can be spiritual (i.e., religiously-minded) without having to give God ten percent of their money or one-seventh of their time because time and money are real, and God is spiritual. Contrast that common gnostic attitude, however you see it manifested, with the Apostle Paul's insistence in 1 Corinthians 15 and 2 Corinthians 5 that the spiritual/resurrection body is very much corporeal.
Camping, obviously, is trying to dodge accountability. Still, it's a clever, even an insightful, dodge.