It's because they judge an Olineman by his failures. But anyone who watches an Olineman knows there are different levels of success on a play. There is no way for PFF to take that into account.
No, there's not. And PFF is crap quite often.
But Collins was a weak link at times. There were several games where he was targeted specifically with stunts, the second Eagles game was one of them.
He is not a great technical blocker at this stage and he can be fooled with mental assignments. He can maul and run and look like the next coming of Larry Allen at times.
He's not a finished product yet. He can get even better. Especially with more experience.