Yes, evangelical preachers who preach that racism is sin will go to eternal damnation in Hell, because they are standing against the Word of God. Racism is not sin, according to the Holy Bible.
Jesus refused to preach against racism, although racism was rampant in His day. In fact, Jesus participated in racism of His society by calling a Syrophonecian woman a “dog” in effect. That is the racist term that Jews used against Syrophonecians. Jesus participated in racism because racism is not sin.
“I warn everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues described in this book, and if anyone takes away from the words of the book of this prophecy, God will take away his share in the tree of life and in the holy city, which are described in this book.”
Racism is not sin. If an evangelical preacher calls racism sin, then that evangelical preacher is changing what the Bible teaches. That evangelical preacher is a false teacher and will go to eternal damnation in Hell, unless he repents (turn away from his false teaching to correct teaching of the Bible).
You must leave the church where the evangelical preacher preaches that racism is sin, because he is a false teacher and is in open rebellion against the Word of God.