If Andrew Bynum was a middle linebacker in the NFL, he'd be flagged for a 15-yard penalty if he did this to any quarterback, whether it's Tom Brady or Chad Henne. In the NBA, he can apparently get away with a simple personal foul as long as he does it to JaVale McGee.
This is the byproduct of the anti-flopping movement. Is it better for referees to fall for some flops, but always whistle legitimate fouls correctly, or is it better to sometimes confuse legitimate fouls for flops? Obviously, you want a balance, but I'd prefer the former.