Does the unchained Barbarian rage power 'calm stance' allow the stalwart defender ability defense stance to be used while in rage?

Question

One of my players is playing a Barbarian that has taken levels in stalwart defender. They have been using the calm stance rage power to allow themselves to utilize the Defensive stance ability of the stalwart defender. I've allowed it so far, mostly because I kept forgetting to look up the stalwart defender.

Does the state of calm part of the calm stance rage power override the restriction on entering defensive stance while raged?

Calm Stance (Ex):

The barbarian can enter a state of calm. While in this stance, the barbarian doesn’t gain any benefits from rage other than the temporary hit points, but she doesn’t take any of the penalties from rage (including the penalty to AC and the restriction on actions she can take). Rounds spent in a calm stance still count against her total number of rounds of rage per day. This is a stance rage power.

Defensive Stance (Ex):

.... A defensive stance requires a level of emotional calm, and it may not be maintained by a character in a rage (such as from the rage class feature or the rage spell).

Answer 1

The text of calm stance answers this pretty clearly:

... but she doesn’t take any of the penalties from rage (including the penalty to AC and the restriction on actions she can take)

clearly, 'penalty' here is not being used in the technical sense of a certain category of numeric modifier, but in the broader sense of 'stuff that's bad for you'. Thus, since not being able to use defensive stance would be a thing that'd be bad for you, you probably don't count as raging for that purpose (but maybe you do cause its a separate source, depending on how the DM handles the 'when does bad stuff from X as a result of Y count as bad stuff from Y' question). Furthermore, because defensive stance's prohibition is a prohibition against taking an action while raging, there is a second case to be made that the specific example given covers the ability to use the power, subject to a different argument over whether the 'the' in '...the restriction...' is refering to the specific text in the rage class ability only or the full retriction of a character's actions while raging on the basis of their raging. That's the rules-based part of this.

For the not rules-based part, the answer is obvious. The defensive stance prohibits rage because it requires a degree of calm. The calm stance power is a extraordinarily great degree of calm. The calm stance power should easily satisfy the requirements of the defensive stance.