I'm not. The notion that you only earn basic rights if you join the military is literally the premise of absurd comedy Starship Troopers.
I think Heinlein actually has a very interesting point. To wield the power of the government (which is what voting is), it is important to be able to act selflessly. If someone can't do that, even for a couple of years of their life, why should they be able to wield that power over others? The universal franchise is not a religious dogma, it's good to ask these questions and think about whether our society could be better if we organized it differently. Unfortunately, a lot of people completely missed the point and just rounded it off to "Heinlein thinks the military should run society", which isn't at all true.
In the book it was said that if a blind deaf person in a wheelchair volunteered for service, the state would find something for them to do. Maybe tediously counting hairs on a caterpillar, or testing chairs in Antarctica.
Now for me the asspull from Starship Troopers that I still think about every now and then was the notion of mathematical proofs of morality at a high school level (or any academic level, for that matter). This was a society that somehow discovered provable objective morality, and I really wish that idea could have been fleshed out more by Heinlein.
You see him put much more thought into political systems and economics in other books like The Moon is a Harsh Mistress, Stranger in a Strange Land, or For Us, the Living.
[1] https://www.nitrosyncretic.com/pdfs/nature_of_fedsvc_1996.pd...
It was not even the premise of the film - only one right was conditioned on service, the right to vote (and possibly hold political office). I.e. actions that wield authority over others. I argue that is not "basic".
These societies literally couldn't have existed without military service.
America has a very difficult time making a similar case, and, often, the case is really difficult to make that they aren't actively harmful.
What we're saying is that if the military gets it first, that's ok, because it's a stepping stone to all of us getting it.
For example, let’s say you want to prevent wealth redistribution, but there is lots of popular support for it. Then you give it to some, for example old people, and it removes wealth redistribution as a priority for them.
Now, you can more easily withhold the benefit from the remaining population. Or give them all various tiers, such as white collar and government workers with more employer subsidies, and lower paid workers with few or no subsidies.
At the end, the opposition group will waste a ton of energy trying to make their cause a priority, and will probably never achieve the full goal. The more politically important will get theirs, and the less politically important will suffer without. That stepping stone becomes a barrier.
In the example, you can change age to skin tone, gender, religious tribe, military status, and even arbitrary geographic boundary. See the recent tax benefits Alaskans received in exchange for their Senator’s vote.
:-(
It's not about giving classes "rights", at all.