I would have preferred they go for it from the 4 as well, but just to play devil's advocate, you can justify the FG IF your sense is that the defense will give the offense another opportunity to take the lead. That seemed to be the idea at the time, which makes the fake punt decision later on all the more baffling.
The way you can justify the fake punt at all is if they went for the TD on 4th down and didn't make it and you don't think the defense will be able to get the ball back.