If I blockade you in your house, is that failure to aid? Or something else? Sanctions occur via commission, not omission. They’re not a failure to render aid or to be maximally charitable. They’re active harm.
If I decide to stop buying bread from the baker in boycott, is that a commission?
It is certainly a change of state, but the status quo does not entitle ongoing purchases. This is a sanction. I can also extend this boycott to anyone else who shops at the baker. That still is not a commission. It is a refusal to interact.
A blockade is different. It is a threat to use force for disobedience. IF I threaten to beat other who willingly shop at the baker.
Moreover, it's kind of consequentialist morality ignores the distinction of active harm versus failure to Aid.
This should play a role when one considers something an attack or weapon.
Is less than maximal charity an attack?
Is it an attack when someone refuses to sleep with someone else?
Norms around choice versus entitlement distinguish the two.