Hi. You may be reading into the “if true“ a bit too much

nothing wrong with that of course. However the purpose of that statement is to remove any ambiguity about the claim. The test writer wants you to assume that the claim is true no matter what facts you may bring from outside of the GMAT.
For example, if they made up an argument and made up a country that that country’s president is making, they don’t want to test takers to argue that since that country does not exist and the president does not exist, that claim is not true. Instead they want you to assume the claim or the assumption ARE true within the scope of the question.
Does that help?
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