One of the central ideas of ageism is the concept of maturity, the linking of undesirable characteristics with age and things typically shown to or understood by children and things typically not shown to or understood by children. However, this idea is flawed, because there is no correlation between being “childish” in the sense of being petty or spiteful, and being “childish” in the sense of enjoying child-orientated cartoons and activities.
You can rank my use of grammar and spelling as mature, and my short temper as childish, or my interest in trauma as mature and my abiding love for My Little Pony: Friendship Is Magic as childish, but you can’t draw a connection between any of them that doesn’t rely on already taking your conclusion as correct (I.E: “But they’re both childish!”).
While you may draw a valid comparison between behaviors typically exhibited by children and those exhibited by adults or adolescents judged childish, I can draw an equally valid comparison between the behavior of, say, depressed people, and the behavior of people who do not want to partake in sports, because both exhibit the same behavior of refusing sports.
Of course, if you look at the wider picture and the varying factors and so on, that link does obviously not prove that all who dislike sports are depressed. Such is the case with ideas like mental age and maturity vs childishness.
But still, ageism can still be a pleasing idea to hold, as can all forms of supremacy based on intrinsic traits can be, and so some people may still cling to it. That’s also flawed. Let’s assume you have a somewhat shorter than average life, and you reach 70 before dying. You will have suffered ageism towards the young for about 18 years, you will then be privileged by ageism for about 10 to 20 years, and then ageism against the old will begin. and you’ll live with that for the rest of your life.
So, all in all, if you live to 70, you will only be benefitted by ageism for at most two sevenths of your life. That isn’t a very good deal, and it only gets worse if you live longer, hence ageism helping you isn’t a very good justification. The only real reason to believe in ageism is that it makes the world simpler, but even that’s going to backfire, because by ageist standards, simplicity is childish.
Ageism has many other flaws. For instance, it can tie into ableism, regarding developmental disabilities, as people with them are sometimes compared to children, and hence all kinds of problematic attitudes about innocence and universal developmentally disabled asexuality spring up.
All in all, ageism is like all other oppressive views in that it’s deeply flawed, illogical and harmful. It’s also akin to other oppressive views in that I don’t think you have a right to call yourself a progressive, believer in social justice, or anything else like that while you invoke it against others.
This has been a somewhat 101-y post by someone who is younger than they’ll admit to most people.