What is the ruling on condemning evil if it leads to insulting the religion?

Enjoining good and forbidding evil is a collective obligation (fard kifayah). If some individuals fulfill it, the obligation is lifted from the rest. However, if everyone neglects it, every able person who does so without an excuse or fear incurs sin.

If there is a legitimate fear of harm, such as murder, beating, or humiliation, the person who fears is excused, and disproving in one's heart is sufficient.

As for mere insults and curses, some scholars do not consider them an excuse to abandon enjoining and forbidding, while others view them as harm and an excuse.

Scholars differ on the obligation of enjoining and forbidding towards those who are not expected to accept advice. However, the view that it is obligatory is held by the majority, as what is required is the command and prohibition, not acceptance.

Allah Almighty says: (And when a community among them said, "Why do you advise a people whom Allah is about to destroy or to punish with a severe torment?" they [the advisors] said, "To be absolved before your Lord and perhaps they may fear Him.") [Al-A'raf: 164].