“But we preach Christ crucified, unto the Jews indeed a stumblingblock, and unto the Gentiles foolishness: . . .” (1 Corinthians 1:23 [DRB])
Some Protestants accuse Catholics of idolatry and for keeping our Christ on the Cross just by depicting Him on the Cross. Muslims tend to accuse us also of the same thing.
The crucifix is a sign of the Christian faith. This is because of the emphasis the Cross has in Scripture and Tradition. As by the Cross He reconciled “all things . . . on earth, and . . . in heaven” (cf. Colossians 1:20). He also obliterated “the bond against us, with its legal claims, which was opposed to us” by “nailing it to the cross” (cf. Colossians 2:14). The crucifix is a sign of our salvation which was achieved on the Cross. Saint Cyril of Jerusalem said, “I confess the Cross, because I know of the Resurrection; for if, after being crucified, He had remained as He was, I had not perchance confessed it, for I might have concealed both it and my Master; but now that the Resurrection has followed the Cross, I am not ashamed to declare it” (Catechetical Lectures 13:4). It is so important that we already see verbatim evidence of the Sign of the Cross in the second century Tertullian said that “in all the ordinary actions of daily life, we trace upon the forehead the sign” (cf. De corona 3). One of the many things we do when we cross ourselves is ponder on the Crucifix (literally “Crucified One”) to whom we must conform ourselves as to “put on the new self, which is being renewed, for knowledge, in the image of” God (cf. Colossians 3:10). It is from the Cross that the Sacraments poured forth and from which they have their efficacy as Saint Thomas Aquinas said that all the Sacraments are “effected in us by Christ’s passion, i.e. grace” (cf. Summa Theologica III.60.3). The Most Blessed Sacrament – the Eucharist – has a special connection to the Passion of Christ as it brings forth that which was shed on the Cross as a reality to us. This is why for many centuries our churches have an altar crucifix, to keep our minds on the Christ whose Body and Blood are offered to us by the altar table. So the Catechism says, “The sacrifice of Christ and the sacrifice of the Eucharist are one single sacrifice” (n. 1367), as Our Lord said, “Take and eat; this is my body. . . Drink from it, all of you, for this is my blood of the covenant, which will be shed on behalf of many for the forgiveness of sins” (Matthew 26:26-28).
The crucifix is a major stumbling block to the Muslims who reject Christ’s Crucifixion since the Quran says the Jews crucified another man, thinking it was Jesus (Quran 4:157-8). The crucifix, the symbol of Christianity itself, is thus despised as a falsehood and idol; hence we are idol-worshippers according to them. Thus they call us “worshippers of the Cross” because we profess Christ crucified and often revere Him such as on the crucifix, i.e. kissing a crucifix at Good Friday liturgy. The Jesus of Islam, which I do not believe to be the same Jesus of Christianity, is said in Islamic eschatology to come fight with the Muslims against the Antichrist and “will break the cross” (Abu Dawud 37:4310); Islamic commentary says this refers specifically to the elimination of Christianity. According to Islamic tradition, “The Prophet said that Allah commanded him to destroy all the musical instruments, idols, crosses and all the trappings of ignorance” (Qudsi 19:5).
Should it be all that surprising then that we see jihadist groups like ISIS destroying churches, monasteries and cemeteries particularly by destroying crosses, crucifixes, icons, statues, bells and other beautiful works of Christian art which were laboriously made out of love for the faith? Don’t believe me? Here’s just one article with pictures of ISIS destroying just one of many churches in lands occupied by them.