BS. Most of us are Christians and as such have a responsibility to call out date-setting charlatans like Camping.
Camping is a fraud. Any good work he's done is negated by all the damage he will do to the foolish people that believed this crap and arranged their lives around it. There are people that have squandered their savings, stopped pursing career opportunities, made buffoons of themselves peddling this 5-21 nonsense, etc.
Camping is no better than any other date-setting con man and does not deserve our sympathy. He should be aggressively and openly mocked. Doing so might just deter the next hack who gets it in his head to push this nonsense.
Indeed we do. Paul called out Peter in Galatians 2 because Peter was teaching things in an un-Christian manner. We Christians are under the same obligation.