John,
That's not may not be true for doors designed to JAA standards. They have to have a pressure relief vent that opens ahead of the main door. Beleive you have to be able to open it against a 0.5 psi pressurized cabin. But I agree it's not designed for high altitude use just to overcome pre-pressurization loads after an aborted takeoff.
All our flight test birds have powered doors (hydraulic ram) that can be opened at high altitudes but are also fitted with special cabin overboard vents that can bring cabin pressure right to ambient rather a preset maximum cabin altitude.