That can't be the argument --- it can't be that NSA simply knows a vulnerability that impacts one very specific lattice scheme and not the others. The reason for that is a cryptographic concept known as the Vizzini Conjecture: the argument you just put forward can be applied to literally any cryptographic standard NIST authors. Since NSA knows that, and knows you know it, you can clearly not choose the wine in front of you. It must be that the standard NIST picks is the only secure one, so that NSA can see it tainted by NIST association.
But yes, this is the useful conversation to have. There are other scenarios! You can get into more detail on where MLKEM came from, for instance.
Yes, they trick me and I pick the poisoned wine... But wait, no, I used a hybrid. Imagine the code can't be backdoored (it's proven not to crash/be slow/be exploitable) so at worst it can make the security no better. At best, the NSA knows a whole new subfield of cryptography (from history: differential cryptanalysis) and it really is more secure.
They laugh at us while we try to think of how 1024 is better than 768: "bigger is better, right?" "does 1024 refer to the number of years it takes Nightmare Moon to break the code?"