Is it correct not to show hatred and disapproval towards someone who has harmed Muslims, in order to maintain relations with relatives?

The transgressor and the unjust person must be abhorred to the extent of their transgression and injustice, even if they are Muslim. When mentioning the unjust, one says: "{Is not the curse of Allah upon the wrongdoers?}" but it is not beloved to curse anyone by name. As for whoever killed Al-Husayn, or aided in his killing, or was pleased with it, upon him be the curse of Allah, the angels, and all of mankind. Abhorring transgression and injustice in general terms is sufficient, without going into detail if detail would lead to severing kinship ties or corruption. One must be gentle with people and invite them to love and obey Allah and to abhor His disobedience. As for whoever loves sinners or the unjust, their case is detailed: between one who loves them for their sin, and one who thinks well of them or does not know their true nature.