Nearly all Baldur's Gate companions were far from optimized, I’m not sure what the fury is about. They were obviously attempting to make plausible characters, not murder munchkins.
Most evil companions in BG1 were ridiculously good, the cherry on top was Edwin who was a better mage than the PC. From the good companions, Coran had an illegal dex score of 20.
Several evil do have better stats, but are far from optimal--they just tend of have a good essential stat. The evil characters like Viconia having 18 WIS, Edwin having the cheat amulet, and Kaigan having an illegal 20 CON are examples. Otherwise they are unremarkable. Tiax's stats are so bad they have him the special ability to summon Ghasts. Coran's illegal DEX and proficiency are also good examples, but he's Chaotic Good. BG1 has a large cast of NPCs (25 of them--excluding EE), and the majority of them are not optimal at all. See
Mike's RPG Center, as reference. It's entirely OK for NPCs to be sub-optimal, particularly when it makes them more believable.