Ideology and Victory Type

I play marathons and I've had several re-rolls so I've not fully explored late game yet.

When you pick your ideology it says "Best victory types". So lets talk about order for example, which is best for science, culture, and domination. Does this mean an order civilization cannot win a diplomacy game or does it just mean that ideology doesn't have any skills that really help that tree?

At first I thought it was once you choose you've elminated a victory style option, but I'm starting to think I may be wrong.

It's just a recommendation. It does not lock any victory types at all. Don't forget, you can switch ideologies as well (for a penalty).

You are wrong. Order does not preclude Diplomacy, it just isn't beneficial for it.