Your son's playmate needs surgery after being bitten by a lab, and that's terrible. If the dog had been a 150# rottie, he would have needed a coffin and a tombstone.
World of difference
There is a large difference between facial stitches, no matter how sad, and dead.
First, I was addressing the comment that labs are "never" mean; an obviously false statement. But since you appear to be asserting that a Rottie attack will end in absolute death whereas lab attacks only end in sad little stitches and years of reconstructive surgery, I'm wondering where you got your stats?