'Passion' meant 'suffering,' not 'enthusiasm' — from Latin 'pati' (to endure). Feelings were things suffered.
A strong and barely controllable emotion; an intense enthusiasm or desire for something; the suffering and death of Jesus.
From Old French 'passion' (the Passion of Christ, physical suffering, martyrdom), from Late Latin 'passiō' (suffering, enduring), from Latin 'passus,' past participle of 'patī' (to suffer, to endure, to undergo), from PIE *peh₂- (to hurt, to suffer). The word entered English exclusively as a religious term — Christ's suffering on the cross. The secular meaning ('intense emotion, strong desire') developed later, preserving the idea that powerful feelings are things suffered, not chosen. To have
'Passion' meant 'suffering' for 400 years before it meant 'intense desire.' It entered English for one purpose only: to describe Christ's agony on the cross (the Passion). The shift to 'strong feeling' happened because medieval theology understood all intense emotions as forms of suffering — things that happen to you against your will, like Christ's torment.