RPM is safety, not unlike altitude in flying an airplane, I imagine. Down-shifting provides the dual advantages of, 1. Increased torque multiplication from the drivetrain (gear ratio), and, 2. Greater horsepower/torque (usually) from greater rpm (from the ability to process additional air/fuel mixture per unit time).
If your bike stalls in second gear, you've received a subtle message you should be in FIRST.
And . . . clutches don't particularly like to be slipped; wears 'em out, even robust KLR650 clutches. Feathering the clutch is sometimes essential/necessary, but . . . discretion in the practice promotes longevity/reliability.