Nope, Calvinism is not somehow uniquely subject to corruption
And I certainly didn’t mean to suggest it is. Indeed, each religious tradition has its peculiar forms of sanctity and corruption. A Calvinist saint (and there are some such as Francis Schaeffer) doesn’t look like a Catholic, Orthodox, or Baptist saint. Indeed, none of them look like each other. But there is a secret bond which still unites them all. C.S. Lewis talks about this and even notes that it extends to non-Christian traditions. He much preferred talking to a real Jew or Muslim than to the vague, watery, homogenous adherents of religious traditions, people “not exactly obedient” to any religious faith. He believed this was because at the core of what was best in each tradition, Christ was secretly at work. I believe the same.
Conversely, when different traditions go to rot, they stink differently. Baptists can’t produce a Rasputin or a Stalin odor. These have a distinct stench of rotting Orthodoxy to them. Likewise, the Orthodox could never give us Robert Tilton, nor does John Shelby Spong smell like anything but decayed Anglicanism. As to rotten Catholic faith, there seems to be a shift. It used to be that bad Catholics smelled like Hitler or (Jesuit schooled) Heinrich Himmler. Since Vatican II, bad Catholics typically smell more like Frances Kissling. The point is, any religious tradition can go to rot, not just Calvinists. But all the traditions have their glories too.