UN not available to build

[Libertarian]

Apparently, you can't build the United Nations wonder — and thus accrue its cultural benefit — if you have deselected diplomatic victory. At least, in my current game, the option to build it doesn't appear in any of my cities. Don't know whether this is a bug or design flaw, but I thought you should be made aware so you don't waste time researching fission for that purpose.

[Badtz Maru]

I hope this isn't true, as I've given it another ability (gain any tech two other civs have, like GL) so it is still useful with Diplomatic Victory disabled.

[Sevorak]

This is, to my knowledge, intended.

With diplo victory off, any wonder with Allows Diplomatic Victory checked will not appear. Design thing, part of the civ lite trend - why show a wonder for diplo vic if it's off? Just makes things simpler, I suppose. I personally uncheck Diplo Vic on the UN and give it more interesting abilities, I just don't see the fun in a diplo win.

Another interesting way to do a no-wonders mod, now that I think about it, just check Diplo Vic on every great wonder and start the game with diplo vic off....

-Sev

[Libertarian]

why show a wonder for diplo vic if it's off?

Culture. It gives culture points. Culture is another way to win. By disabling the UN, they've penalized empire builders.