Ailerons did react but roll rate limitation probably did apply as well.
You are right, the roll rate limitation could have been the cause as well. But the ailerons did not react as the pilots expected them to do. In such a thrilling second you expect full aileron, if you give full input. There is just no time left to think about internal flightcomputer modechanges or envelope protections and how you can counteract them. There was no time for pulling CB´s in Hamburg either