A lot of people find closed positions boring and stale. For example:
someone may consider that to be boring. Someone may consider that to be exciting. I am the second person. Maybe he doesn't like certain lines that appear very often. It's not up to other people to judge someone else's tastes.
bf5 isn't a kings indian though, should play e5
e5 is the mainline but from Boris Avrukh's latest Gm repertoire book, "it is not played as much at high level anymore due to dxe5". White gets a nagging advantage which I feel does exist, if I knew the theory at least. Bf5 is definitely a king's indian move. e5 was the old mainline.
The mainline for the fianchetto is apparently a6, Bd7 and Rb8. or a6, Rb8 without Bd7. I see those much more often. Bf5 isn't common, but it is a viable move.
honestly doesn't make sense tho, its equivalent to saying that the najdorf has no theory...