That's wrong, all FX cards have support for ps 2.0.
That was a big part of the marketing for the fx cards, however they tended to perform badly under 2.0, so Microsoft and Nvidia had to develop a new shader version called 2.0b, which was optimized for the FX chip.
That thread with card caps is odd because none of the cards show ps 2.0 support, even though many of them have it...that may be from the directX 8 version of A6.