At the end of the day there is always option to block users whose posts you don't want to see.
It's a better solution then forcing your own beliefs on everyone.
We all know people who want "political discussions" forbidden aren't interested in merely not being personally affected by it (negatively or positively), they want
others to be punished for it or limited in some sense. It isn't about convenience, justice or whatever.
As for DU, he probably just doesn't want Codex to get "bad reputation" for discussions herein, and wants to preemptively ban them so that he be spared retaliation from Twitter or whatever. An understandable position, if a bit pathetic.
Better enforce stronger and clearer rules in non-GD forums. You don't want people to say the "n-word"? Then clearly state so in the rules and enforce it. Don't want people to speak badly about Jews? Say so. Instead of this frankly childish and tiresome kwetching about what should be done.
Where's that black man who said "online harassment? move away from the screen bitch!", because goddamn. There are countless threads with innumerable insults, lies and propaganda against Islam here, and even calls for genocide of Muslims (hi irenaecuck), on account of that in some countries this whole site would be purged out of existence and everyone arrested for "hate crime". Grow the hell up people.
And lastly, again, Codex isn't nearly as influential in any way, either for or against the right or the left. There's like couple of dozens users who frequently post in GD. Wow much extremism there. How out of touch with outside world one has to be to think Codex in any way has any influence on real societies? Overblown as usual.