Was trying to explain my position to the missus: if the only requirement to be able to vote was stating you want to vote, anyone wanting to disenfranchise others will have to start from scratch.
Right now it's just quietly accepted that felons, undocumented immigrants, and the directly disenfranchised groups (minorities and the poor in various locations with voter id/etc laws) can't vote.
Someone wanting to add to that group can do so from behind a layer (or several) of obfuscation and they're just adding some amount onto a larger amount.
Having everyone capable of representing their wishes (even if not always their interests necessarily) means those trying to be disenfrachised would far outnumber those wanting to remove their rights, this would be a much sketchier political fight than "well, felons can't vote, so let's just add to the definition of what a felon is" like we have now.
Prison conditions are shit, confining people individually is torture, using prisoners as slave labor is outrageous, but the people who would be most invested in trying to fix the laws which allow this: former prisoners, are by and large disenfrachised, which is fucked up, and people who benefit or even directly profit from the prison situation end up having all the say for said prisoners, which is so fucked up there aren't words that express the string of consonants and growling noises it should elicit.
Yet this is how it has been all our lives, and it's easy enough to justify an argument like "well, if you want to vote, you shouldn't go to prison" from a nice safe distance. Shouldn't be undocumented, shouldn't live in certain parts of the country and be the wrong color/below a certain income level either!
Ultimately I would rather someone I disagree with be allowed to vote than anyone be prevented from taking part in government when they wish to do so.