Ye well the thing is, the SCRA may need supplies but why exactly from the faction that is a symbol of ruthless capitalism, indeed having the phrase "richer than you" on its ID, instead of some small firm or sympathizer movement? The exact same question came up to me, but I think it's easy to reply.
Alvin came with the Soviet Union as a parallel example which is a logical choice, so I'll use that again. The SCRA, just as much as the Coalition or the Soviet Union is not the perfect incarnation of communism, they're all aggressor dictatorial regimes flying under the flag of equality and good. I could come up with the thousand times heard argument of "how awesome communism would be if it could materialize", so it's entirely justified.
But why exactly the IND? Obviously because they sell all the stuff the Coalition needs at the cheapest possible price. Why don't these models of communism care about the IND's reputation and what they represent in general? Because their leaders (as all people in leadership, communism or not) care more about their budget than idealism.
Why doesn't the common folk object then? An extract from a movie comes into my head, anyone seen "Goodbye Lenin"? Basically, a few guys make their dying, communist mother believe the DDR (or GDR, you Westerners) keeps on living after it was dissolved, and when all the Coca Cola ads start flying around, they simply say it's because the westerners are attracted by the awesomeness of communism!
Hence, I wouldn't use the argument of "communists need supplies," rather the "communists are human too" one.
Totally makes sense in-RP imo, even if no one actually had this line of thought before.
