I see you're flying a California flag on your freeper page, SD, so I suspect you had a dog in this fight...the 49ers.
I didn't. I'm a Cincy native, and I have no love lost for the 49ers, but I'm not a Ravens fan either.
The refs allowed a lot of bumping and mixing it up throughout the game. The Ravens were hurt by PI throughout the game, imho.
But, I watched that final PI you're talking about, and the DB made legal contact with the receiver coming off the line. The RECEIVER continued in the direction of the DB maintaining the contact and then attempted a bit of a break to the right but did so maintaining hand contact to the DB's upper body. All along the DB was ALSO maintain contact with the receiver.
It was an excellent no-call by the official, who had not called it tightly the entire game.
If the SF DBs had maintained contact anymore throughout that game, they could have opened a Velcro outlet.
It was a good game. Your team lost. (And got a huge break with that blackout when the momentum was clearly bad, bad juju for them. Even an SF fan would have to admit that.)