Your comment intuitively seems correct, and I'm inclined to agree with you. But I can't help but wonder if you just end up picking examples that support this claim. Most examples of corporate wrong-doing probably can't be correlated with traits of their CEO (they're just mistakes made by inept, or possibly malicious, individuals or groups).
Statistically, some percentage of corporate wrong-doing will correlate to some event in the CEO's past. I'm not sure that necessarily means that we can point to those cases as proof that a fish rots from the head.