Providing the ‘evil eye’ the status of ‘divine decree’, I think, is going too far. But still, I agree with the following part in the link ( Islam Question and Answer - Definition of the evil eye, and ways of protecting oneself against it and treating it ):
“The evil eye is like an arrow which comes from the soul of the one who envies and the one who puts the evil eye on another towards the one who is envied and on whom the evil eye is put; sometimes it hits him and sometimes it misses. If the target is exposed and unprotected, it will affect him, but if the target is cautious and armed, the arrow will have no effect and may even come back on the one who launched it.”
Perhaps, that is the precise reason why there are so many prayers for the safety from all kinds of evil. I would think that evil eye is one of the many forms of evil.