[Skarg]

That sentence is also defining what a charge attack is, so naturally a charge attack is an attack.

Unfortunately, when mentioning defending against charges, Steve efficiently says it applies against a charge attack. Someone might take that to literally mean it can only be applied against people who are running up and also actually attacking, if they think that's going to be a better way to play, but:

1) That doesn't seem to me to make any sense, and I don't think can really be the intention.

2) When a polearm is defending against a charge, the attack in question is the polearm-user's attack.

3) Shorter weapons are never attacking at the point in the turn where this determination is made. So such a condition would never apply to them.

4) Figures in TFT can change their option, and in practice rarely if ever even mention what their option/action is, until it's actually their turn to act. So not only would a shorter weapon not have declared an attack during the polearm phase, but they also could say they were intending to do any other legal option (to make a legal argument that they can't be attacked by a polearm during the polearm phase), but then change to Attack when their adjDX comes up.

5) If figures could avoid polearm effects by taking some other option, charging polearms and using a non-attack-option to deny their effects would be the standard (effective and weird) practice to do so, and would've been mentioned in the rules and earlier discussions about polearm situations, but there is no such mention except recently in these forums.