There's an asymmetry between discussing flaws in the admin's plans and discussing flaws in the attacker's plan

Not quite, the defence and the attack are a matching zero-sum pair. Aiding one disadvantages the other.

The national security analog of the former is pointing out security holes, and the analog of the latter is giving helpful advice to terrorists.

Pointing out security holes is routinely called "giving helpful advice to terrorists" (or other members of the unholy triad, child pornographers and drug dealers).