He's one of the best kickers in the league. He can hit from 51. He missed from 60. Regardless of what you think of the defenses ability, you do what you can do get him to kick from 60.
If the guy's range was 45 yards, and he was going to kick from 40, you'd move him back on a penalty, right? if his range was 35 yards, you'd move him back from 30.
If the Bills were facing a kicker with a shorter range, or were playing in a rainstorm, 51 yards is out range. But those weren't the circumstances.
Bironas has a range of 50-55 yards. It's a no-brainer, you move him back if you get the chance.