So I think it has been decently documented about how some feel Looney had a relatively good night against the Ravens and how others and including MB reviewed Looneys game much differently. Well Barrows made an interesting statement in his latest column which I think shines some light to his prior reasoning.
"De facto right guard Joe Looney had a mixed game against the Ravens on Thursday but seemed to have improved his technique during the three days of practice. He did not stand out, which is good for an interior lineman.
Read more here: http://www.sacbee.com/2014/08/12/6622679/offense-where-things-stand-in.html#storylink=cpy
So the bolded points out a common technique for viewers to rate linemen. Which Martin and than Looney both did in the first series of the game. Martin flopped on a pull to his side of the field and Looney got blown up on 3rd and short. But that does not answer the question of why nobody Noticed the most glaring mistake on the second play of the game by Iupati that got Kap planted on his back in under 2 seconds and his repeatedly horride pass protection in the two drives. FYI Barrows second line of support for Looney's play was that we did outstanding running to the left side of the field and did not run to the right.
The problem with the OL stand out approach is that it is highly dependent on the direction, especially for the interior OL. Naturally our eyes pick up things in the fore ground and often filter out things in the perceived background. 49ers were traveling from left to right on the screen putting Looney and Martin in the foreground and hiding Kilgore and Iupati.
It is not to my surprise that most people who rewatched the game reviewing each play for each OL came to a much different opinion than people watching it live and/or reviewing multiple players per play like MB would do. You cannot watch an entire trench battle in one viewing, it really takes 5 viewings to see exactly what happened each play, two and three times really isn't even enough to get a specific judgement on all 5 battles.
Had 49ers been playing from right to left, we would most likely be talking about how Iupati had a bad performance, that he's always been a better run blocker than pass blocker, that his prior injury is still possibly effecting him and how Looney looked solid, and good luck to Boone and his future endeavors.