What is meant by the prohibition against cursing the dead?

The questioner : What? The prohibition against speaking about the dead?

The Shaykh : Yes, do not curse the dead.

The questioner : Yes, this does not contradict this hadith, given that he spoke ill of her.

The Shaykh : What is meant by cursing the dead is for a person to speak ill of someone without a valid purpose. However, if it is for a valid purpose, there is no harm. For this reason, it is permissible to curse a deceased person who was an innovator (mubtadi') and it does not cause harm.