>>23384432
>And it wasn't shown because it had nothing to do with the story.
Stories are supposed to be consistent with themselves. If the characters go to Earth and there's no Federation presence and plenty of Zeon's, this tells the audience that the former has little power and the latter has plenty.

>You can't tell me that after Gelgoog all they've spammed are Big Zams and Gyans.
Those were the personal guards of Gihren and Kycilia, respectively. In all likelihood, the regular army is gradually being shifted from Zakus to Gelgoogs, like how the US and other air forces are changing their old F-16s and F-18s to F-35s as soon as they come off the plant.

>As for how Chalia got to Earth and back, it could be a number of things
You don't need to come up with contrived reasons when it was explained by "Khara's President" on Twitter: Zeon has a large military presence on Earth for geopolitical reasons. Therefore, the Federation can't do much to stop them ("set up in a semi-forceful manner").

>Because they got no good enough reason to do anything except for sending a concerned letter.
Don't be stupid. Why wouldn't they send even a small contingent of ships to do even basic observation, if they had the ability to do so? Because... (you should be able to solve this).

>There's a good reason why Side 6 officials looked down on them.
And yet they didn't have the national power to stop Zeon from intruding. Pride means nothing if you don't have the force to sustain it.