I don't think the book mentions (directly) where Johnny went to school (though it does mention his heritage at the end), but suffice it to say 'Rico' probably isn't considered foreign there.

Also, civilians in The Federation have nearly identical rights to citizens (the book elaborates on this more later.) The only distinctions between civilians and citizens are citizens have completed the required (2+ year) term of service in the duties assigned (as stated in chapter 2), and are allowed the privilege of voting and serving in government. And as mentioned in the chapter, literally the only thing that can prevent you from serving a term other than your own choice not to do so, is being ruled mentally unfit to comprehend the oath (which some of the jobs mentioned in chapter 2 and throughout the book indicate is a very low bar, not some sort of onerous literacy test.) In fact, I'd imagine if one of the skinnies from chapter 1 showed up at a recruiting station and indicated they wanted to serve, I don't think they could be turned away.

(For others that have read the book before, please note that I am trying to avoid spoiling anything for those that haven't.)