I don't know whether there is a bias against Carter more than the neglect of wide receivers in general. Chris Carter had HOF numbers when he retired. He was second to only Jerry Rice in his production. Even now, his 1101 receptions is 4th all time as is his 130 TDs. Unfortunately, time is not on his side, as his competition from the pass happy NFL of today and tomorrow will only increase in number and decrease his chances. Maybe he'll become the NFL equivalent of Bert Blyleven, or maybe he'll have to do a Harry Carson.
Cheers!