I'm not sure how we are supposed to demand resources, but right now, right clicking on the 'give' buttons does the same thing as left clicking.  Ultimately, this is more or less consequence free, but is a bit inconsistent with the 'click to increase, right click to decrease' concept seen in the black market and elsewhere.  I only found this out because I thought perhaps right-clicking would issue a demand.

I was playing advent when this was discovered, and haven't checked the other races, but this seems like a race-independent issue.  I did have the appropriate tech (overtures for advent) when I tested it.