The problem isn't in correcting error, but the manner in which it is done.
let's use Fundi, for example.
he was called out in every thread for dismissing the True Word of God.
he claimed Speaking in Tongues is what Saves you.
he claimed the Bible is outdated and Science should be viewed as the correct authority on Gender Issues.
he claimed it was the FATHER, even though the Bible specifically states the Holy Spirit, gives the Utterance to Speaking in Tongues.
he promotes Mormon Videos.
he DENIES the pre-incarnation of Jesus Christ!
he DENIES that it was the WORD in Exodus 3 and 6 that gave names to Himself like Elohim, I AM TO BE, LORD, MOST HIGH GOD, YHWH, Yahweh!
and this is the SHORT LIST and there's literally another 20+ examples i can give.
so, there's a WHOLE PACKAGE of examples here of what he is doing.
how many times do you say, no no no no no no no before saying, You're a LIAR, a DECEIVER, FALSE TEACHER, and you need to yank your head out and GET RIGHT with GOD?
if i followed your approach, he would still be the same ole person until he dies.
I believe, the effort should be made to stop it now so he can be Saved.