The reasons people don’t see ageing as the problem it is can be easily summarised as misinterpretation and misinformation.
For the ‘misintepretation’ category, we have two common mix-ups.
People mix up chronological ageing with biological ageing. I’m not joking. Some people really do. Chronological and biological ageing are not at all the same thing. The first is just the passing of time. Your chronological age just tells how long you’ve been around. The latter is a wear-and-tear process causing your body to fall apart with the passing of time. Chronological ageing does not imply biological ageing; there are (few) animals who do not age biologically, like the Hydra, for example, but they’re not frozen in time (duh). However, biological ageing does imply chronological ageing: Your body can’t fall apart if you’re frozen in time. (Or just frozen… Ever heard of cryonics?) Chronological ageing is okay: The passing of time lets you do things, make new experiences, and stuff. Biological ageing sucks: It makes you sick and it kills you. Don’t mix up the two things. Don’t be that guy.
People mix up ‘normal’ and ‘natural’ with ‘good’ and ‘morally justifiable’. Again, they’re not the same thing. Malaria is natural. If you catch it and your immune system isn’t strong enough and/or you don’t receive treatment, it’s perfectly normal and natural that you will die. Is that ‘good’ or ‘morally justifiable’? Of course not! So you can’t just say, ‘Oh, well, ageing is natural, so it’s okay,’ and just shake it off.
For the ‘misinformation’ category, we have two typical human behaviours.
People tend to ignore bad things. It takes a while before a human starts experiencing age-related diseases and signs of biological ageing, at least a few decades. It’s more than enough time to put it out of your mind, and eventually accept it as inevitable and convince yourself it’s not a bad thing. As you subconsciously compute ageing is inevitable + ageing is a really bad thing = holy shit there’s an inevitable, really bad thing awaiting for me, you realise the only way to avoid being driven batshit crazy by the thought is changing your views and not seeing ageing as a bad thing, or at least never thinking about it. It’s a basic defense mechanism.
Biological ageing is so sugarcoated it can give you diabetes. They call the last few decades of a person’s life their ‘golden years’, and that’s gotta be the most shameless attempt at sugarcoating in the history of human kind. They tell you being old is good, because you have a lot of life experience and have (assumably) accomplished many things, except that is a (possible) consequence of chronological ageing, not biological ageing. You made life experiences and accomplished things because you had time, energy, and will-power; getting biologically older only makes all of that more difficult, and eventually impossible.