I wouldn't say they are immune -- all people have all kinds of social biases and we construct our lives around them every day.
And yes there's a group-think mentality toward player evaluation in the NFL (which is how you get Brady and Wilson drafted where they were), but people trying to extrapolate that into 'Taylor was a first round talent drafted in the sixth round because all white GMs think black quarterbacks can't read defenses' or even worse, 'the Bills are sabotaging their QB because he's black', is absurd.