How can one sincerely repent of backbiting entire peoples by describing them with derogatory characteristics, knowing that this backbiting was not recognized as such at the time it was uttered?

The fatwa we issue is that mentioning the people of a country in a negative light is not considered prohibited backbiting (gheebah), as long as it is not intended to generalize to all the people of that country. This is because the speaker does not intend all the people of the country, but rather some unknown individuals. Based on this, it is not considered backbiting that necessitates seeking forgiveness (istihlal) due to the difficulty of doing so. However, one should guard their tongue from such statements and seek Allah's forgiveness and repent to Him.