But the President is not selected by Congress, as the PM is selected by the majority in Parliament. Parliament already had a giant "Check" on the powers of the PM, they can remove him from office by a "no confidence" vote.
WHile Congress can remove the President, it cannot do so simpily because they don't like his polices. The situations are not comparable.
Also at the time the US Constitution was written, the King, and not the PM had the power to declare war. We didn't like Kings and were not about to make the President an elected King. The President is the Commander in Chief of the Armed Forces, as was the King of England at the time.
“The situations are not comparable”
Maybe or maybe not. People are not criticising that on this basis, but posting (with greater or lesser degrees of hysteria) that removing this power from the executive is somekind of death knell for the UK and will affect our ability to defend ourselves. In actual fact, most Western democracies, including the US, vest this power in the legislative rather than the executive branch.