This argument relies on false equivalence and a straw man. It compares accusations of being a "Russian agent" to U.S. alignments with Islamists, but the two are not analogous. It also presents a false dilemma by asking if the U.S. is "captured" by Islamists, ignoring more complex geopolitical factors. Additionally, it implies causation (U.S. involvement leading to Islamist takeovers) without considering other historical influences. While the argument raises a valid point about shifting alliances, it does so using misleading rhetorical techniques.
In a political sense, well, that's much more debatable. The problem there is that because the US itself did not feel threatened, US aid came with a price tag: the impoverishment of Britain and the demolition of the trade barriers around the British Commonwealth. US aid was on a cash-only basis until Britain had spent all its hard-currency reserves (both gold and negotiable securities). Then came the Lend-Lease agreement -- arguably the point where the US truly entered the war -- and its price tag was explicit, although unadvertised: the agreement itself contains a clause stipulating the removal of the Commonwealth's trade barriers.
