Just like 16 years old people can’t vote because too young, 80+ years old people should not be able to vote, most of them are too distant from everyday reality of younger people to be able to take a wise decision for the community and also often stick with (way too) old ideals from their years
Not saying what we have is perfect, but its probably as good as its going to get. Its quite coherent actually, as soon as you are a legal adult, you can vote and that right can’t (in theory) be taken away from you. Even as it is, evil people try to find all types of way to dissuade, invalidate and suppress voting. I actually think the majority of people wants the best for everyone, that’s why there is all this effort to remove as much votes as possible. Restricting by age would would add to that.