If churches practiced the immediacy of baptism as did the apostles and early church, I'm not sure this would be our question. The requirements for baptism is repentance toward God and belief in the Lord Jesus Christ, and a credible profession of such. If continuing headlong in their "obvious sins" proved their profession of contrition and repentance to be false, then the church would deal with that through church discipline.
In Acts 2 it appears that the 3000 were baptized upon their "receiving their word".
Acts 2:37 ¶ Now when they heard this, they were pricked in their heart, and said unto Peter and to the rest of the apostles, Men and brethren, what shall we do?
38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
39 For the promise is unto you, and to your children, and to all that are afar off, even as many as the Lord our God shall call.
40 And with many other words did he testify and exhort, saying, Save yourselves from this untoward generation.
41 Then they that gladly received his word were baptized: and the same day there were added unto them about three thousand souls.
42 ¶ And they continued stedfastly in the apostles’ doctrine and fellowship, and in breaking of bread, and in prayers.
In Acts 8 we have the example of how Simon was dealt with by the apostles:
Acts 8:9 But there was a certain man, called Simon, which beforetime in the same city used sorcery, and bewitched the people of Samaria, giving out that himself was some great one:
10 To whom they all gave heed, from the least to the greatest, saying, This man is the great power of God.
11 And to him they had regard, because that of long time he had bewitched them with sorceries.
12 But when they believed Philip preaching the things concerning the kingdom of God, and the name of Jesus Christ, they were baptized, both men and women.
13 Then Simon himself believed also: and when he was baptized, he continued with Philip, and wondered, beholding the miracles and signs which were done.
14 ¶ Now when the apostles which were at Jerusalem heard that Samaria had received the word of God, they sent unto them Peter and John:
15 Who, when they were come down, prayed for them, that they might receive the Holy Ghost:
16 (For as yet he was fallen upon none of them: only they were baptized in the name of the Lord Jesus.)
17 Then laid they their hands on them, and they received the Holy Ghost.
18 And when Simon saw that through laying on of the apostles’ hands the Holy Ghost was given, he offered them money,
19 Saying, Give me also this power, that on whomsoever I lay hands, he may receive the Holy Ghost.
20 But Peter said unto him, Thy money perish with thee, because thou hast thought that the gift of God may be purchased with money.
21 Thou hast neither part nor lot in this matter: for thy heart is not right in the sight of God.
22 Repent therefore of this thy wickedness, and pray God, if perhaps the thought of thine heart may be forgiven thee.
23 For I perceive that thou art in the gall of bitterness, and in the bond of iniquity.
24 Then answered Simon, and said, Pray ye to the Lord for me, that none of these things which ye have spoken come upon me.
I seems to me Baptism should follow an repentant confession of faith in Jesus Christ as Lord. Discipleship, teaching, correction and church discipline are to follow. As for the KKKer I would talk privately with him about the his attitude. I usually wait a week or two before baptizing to arrange things, invite family and friends, talk with parents if the baptism canidate is a child and deal with questions like the OP.