http://www.ntsb.gov/publictn/2004/AAR0404.pdf
Here's the relevant extract from the training programme as quoted by the NTSB report (page 85).
• Apply climb power
• Maintain 15º to 30º deck angle
• Respect the stick shaker (Fly in the PLI [pitch limit indication])
• Now roll alternately left and right to 40º of bank –
MAINTAIN HIGH AOA• First, use only ailerons and spoilers
– Note: Sluggish roll response – Developing sink rate
• Second, use only rudder – (smoothly)
– Note: Improved roll response – Developing climb rate
• Third, practice combination (both aileron & rudder)
– Note: Optimum roll response
It's clear a trainee might conclude that rudder inputs are always to be used as roll rates are improved. However this is intended for high AOA situations (close to stick shake), AA587 was accelerating through 255 knots and climbing in a normal attitude so AOA was low.
The NTSB often has to use words like possible and probable. Even lawyers have to accept the concept of doubt. The point made was not that AA's training was at fault, but that a trainee might have applied it in the wrong situation. Testimony about a previous wake turbulence encounter seems to support this conclusion (pages 12-13). So it's hard to see how a lawyer could make mincemeat of the possibllity given the supporting evidence.
The report quotes the initial bank angle deviation as 10 degrees (from the 23 degree banked turn). Not an unusual attitude by any standard.
Certainly Boeing (737) suggest that cautious use of appropriate rudder pedal input may be necessary to assist in recovering from a nose high low airspeed attitude if elevator or stab trim is insufficient to drop the nose, and a roll input is needed to allow the nose to drop to the horizon.
That says it's for nose high, low airspeed conditions. Note also it says "cautious use". Repeated full reversals were employed on AA587. The pilot may well have assumed the rudder limiter would take care of structural issues, but this is not always true for an A300-600. Even if the A300-600 did have a rudder limiter (and not a pedal limiter), the stresses imposed may not have prevented the fin shearing off.