One of the Traps of Iblees!

Ayatullah Shahabadi (rh) would say, ‘Never curse the unbelievers regarding whom it is not known that they will leave the world in the state of unbelief. If they leave the world as rightly-guided servants of God, their spiritual rectitude may prove to be an obstruction in the way of your own spiritual advancement.’

In any case, beware that the Devil and the carnal self (nafs) make man enter the preliminary stages of ‘ujb (self conceit); and from this place, step by step, they slowly take him to higher stages of ‘ujb, and in this way, in degrees, they lead man to the wretched state in which he thinks that he is conferring a favor on God by having faith in Him and performing virtuous deeds. This is the final stage of ‘ujb.

Ayatollah Khomeini (rh)