Paul said why Christians him not to baptize read it here,
1 Corinthians 1: 17. For Christ sent me not to baptize, but to preach the gospel: not with wisdom of words, lest the cross of Christ should be made of none effect. 18. For the preaching of the cross is to them that perish foolishness; but unto us which are saved it is the power of God.”
Notice it has to do with not making the cross of Christ of no effect. The cross puts to death all our works of the flesh or diverse washings and carnal ordinances or any work of righteousness that we can do to glory in our flesh. That is the reason as Paul says that Christ sent him not baptized as I understand from the clear text. He was not just talking about them dividing into sects and baptizing in others names.
Were a similar thing when severe pressing circumcision another work of the flesh to glory in if they did it fit salvation.
Galatians 6: 12. As many as desire to make a fair shew in the flesh, they constrain you to be circumcised; only lest they should suffer persecution for the cross of Christ. 13. For neither they themselves who are circumcised keep the law; but desire to have you circumcised, that they may glory in your flesh. 14. But God forbid that I should glory, save in the cross of our Lord Jesus Christ, by whom the world is crucified unto me, and I unto the world. 15. For in Christ Jesus neither circumcision availeth anything, nor uncircumcision, but a new creature. 16. And as many as walk according to this rule, peace be on them, and mercy, and upon the Israel of God.”