Why are NPC parties so bad?

[Thangil]

Alphinaud healed the big pull at the start of Mt Gulg. You know the like 4 or 5 packs? I did that with Alphinaud.

As for them doing low damage, it's because they are trying to make the dungeon run last about 30 minutes and only do single target attacks. They want faster runs of 20 minutes or less to be something you get players for.

Then why is is COMPLETELY DIFFERENT when playing with my squadron?