Do you mean this bit ?
Gal 1:9 "As we have said before, and now say again: if anyone may proclaim to you good news different from what you received--let him be accursed!" (LSV)
So, Paul is saying " If you say anything different to what I say, then curse on you".
And that's how we end up with theocracies . It's also what dictators say.
So much for freedom of thought and all that stuff.
And here is the strange thing, to me anyway. Paul never even met Jesus. He just claimed to have a vision. He goes on to say:
Gal 1:11-12 " And I make known to you, brothers, the good news that was proclaimed by me, that it is not according to man, neither did I receive it from man, nor was I taught [it], but through a revelation of Jesus Christ" (LSV)
So Its what Paul claims was told to him. To him personally. Never mind the Apostles who actually wandered around with Jesus and knew him. They are brushed aside.
And people believe Paul. Why? Why would Jesus appear, pick Apostles, call Peter his rock on which to build his Church, then apparently toss them all aside in favour of some dude he had never met, who on the road to Damascus, hundreds of miles away from where his mates, the Apostles, were doing their commune thing ?
Surely Christians should really be called Paulines. Or many of them anyway. Not the red letter Christians of course. The Jefferson Bible is better for them I suppose.
Incidentilly, a fella named Hong Xiuquan ( 1814-1864), did similar to Paul. Except he claimed to be the brother of Jesus. People believed him, and about 20 million died in the subsequent Taiping Rebellion. It's maybe not a great idea to believe people who claim visions.