NFL Player's Association -- It's Our Duty to Defend Greg Hardy ... No Matter the Criticism

The NFL Player's Association is NOT backing down from its decision to go to bat for Greg Hardy -- claiming the PA has a "duty" to fight for his rights as a player ... despite public outrage.

The P.A. has been under fire for appealing Hardy's original 10 game suspension -- even though it reportedly saw the photos of the damage he allegedly inflicted on his then girlfriend.

Several high profile people -- including Bill Cowher -- lashed out at the P.A. for the move ... essentially saying it should NOT have fought for Hardy because the act was so reprehensible.

The issue at hand is that the Hardy incident went down BEFORE the NFL's personal conduct policy was beefed up -- so the P.A. appealed, arguing that he should have been disciplined in line with the old, weaker guidelines.

Hardy won his appeal, thanks to the NFLPA, and his suspension was reduced to 4 games.

Despite the criticism, Carl Francis -- Director of Communications for the NFLPA -- tells TMZ Sports, "We stand by our decision to appeal his suspension."