It's difficult to imagine a connection to a country which does not allow you to vote. That's not to say that if you aren't allowed to vote you don't love your country or you're not patriotic. But you have no say. So where's the "connection"?
"My take on American history is that the founding fathers meant for the rights enjoyed by the ruling class to eventually be enjoyed by all people"
All people or all citizens? Big difference. All citizens or certain citizens?
Did they mean to extend voting rights eventually to children? The insane? Foreign visitors? Illegal aliens? They are also people (persons). They all enjoy the inalienable rights to liberty and life.
Granted, we have expanded the definition of "the people" through the amendment process to include nonwhites and women. But it still doesn't include all persons or even all citizens. It still, today, refers to a select group.
"People", "citizens", yes, there is a large difference in legal terms, and as you point out, there are limits to both. For example, you must be of a certain age to vote, or be at least 18 and not be judged to be crazy in order to lawfully possess a firearm, etc., etc. But as you stated earlier, the Constitution's language does not provide these details, and as I pointed out and you verified, refinements were made at a later time, and continue to be made. Most of the restrictions were for the states to decide, the fundamental principle of Federalism. How far we have strayed...
And to add even more shades of gray to the mix, you have instances were an 11-year-old kid uses his dad's .45 to kill a house-instruder threatening his mom, and despite his not legally have the ability to do such, is not charged with any crime. Real life demands a case-by-case study; there can be no justice when laws are absolute, a reality that the founders knew all too well.