That's largely because passer rating is greatly influenced by TDs thrown and doesn't take into account rushing TDs. If Allen had thrown for his 8 rush TDs his passer rating would be within about 8 points of Rodgers at 111.
Mine was the TD to Diggs on slant. At top of his drop he reads safety shading Davis deep and immediately switches to throw into Diggs route for YAC and TD. Top level QB stuff