#gundam 00

Depends on the Gundam continuity.

Universal Century, After War Gundam X, 00 et seq., Iron-Blooded Orphans: the mecha have a fusion reactor that emits a handwavium particle which interferes with electromagnetic waves (unshielded electronics, radar, radio, IR, less so visual frequencies but still enough to blur lasers beyond a few kilometers), so combat has to be conducted in-person, and (according to later-written UC worldbuilding) humanoid body plans are easier to control for zero-G attitude adjustments via limb repositioning.

Mobile Fighter G Gundam: Earth is a boxing ring, so of course you'd want the singular mobile weapon representing your country be as easy to control in martial arts by using a motion-capture suit, which means the mobile weapon needs to be humanoid.

Iron-Blooded Orphans, Witch from Mercury: Brain-computer interfaces are most-easily used to control humanoid mecha.

WfM: Maybe something about precision warfare in a setting where mecha developers live in fragile space habitats? But primarily corporate dick-measuring contests.

AGE: A vault of sealed history is leaking archaeotechnology.

SEED et seq.: Arms race from power-assisted spacesuits.

00 et seq.: One Super-Intelligent Dude decides that humanoid power armor is the future of war.

Wing: One secret military group starts making mobile suits because they think they'll get military advantage or something.

Various SD Gundam: Because they're little guys.

Well then, it's official. Togenashi Togeari IS a Bandori band /j

I need the demonstration Enact (and Ali's version too)

I need the Tieren Taozi (and the Tieren Space Type)

I NEED the Garazzo and the Gadessa (and the Gaddess)

And I need need NEED to army build the Sol Braves