nikkas get hit by that pull counter because of how quick it is and they're not expecting it.
Both Floyd and Ali were/are exceptionally quick for their current weight divisions
If you noticed, he hasn't used it in a few years... The Mosley fight was the last time i seen him land it cleanly. He hit Cotto with a struggle pull counter a couple times that didn't land all that flush. I don't think he has the reflexes to pull it off anymore.