First is that Government's way of presenting the data hides the immense level of unemployment of older people. The official records show that unemployment in the 50-64 year old age group is relatively low. But this is a construction based on the exclusion of nearly a third of people in this age-group as 'economically inactive'. In fact the unemployment among older people is massive, and much worse than younger age groups once this is taken into account. Indeed those older people that are classified as actively looking for a job find it much more difficult (they remain unemployed for much longer than average) than younger people.
Of course the figures then assume that people over 65 don't exist for unemployment purposes. They've got a pension, so they don't count. People in this age group who complain about age discrimination in employment are just laughed at. From an economic point of view, never mind individual rights angle, this is really stupid.
If we want a better economy, we need more people working - as opposed to more people living off their savings or state benefits, which should otherwise be invested in sustainable production (solar or wind power perhaps?). Ok, we shouldn't force people to work when they've had enough - but why make it difficult for older people to do stuff when they want?
The second way that society is institutionally ageist is the way that there is an incipient (sometimes overt) bias against older people in employment. When I was 31 (that was in 1983 by the way) I remember going to an IT training event put on by some government agency. Big affair. I got to see an adviser who then told me that I was too old. Apparently this age discrimination is a big thing in IT still. Of course these days it is against the law to overtly discriminate, but sometimes the veil falls off the implicit discrimination, as is the case with the Facebook story revealed today.
To many of course, the fact that the establishment, with all its many ills, is run largely by older people acts to obscure the suffering faced by the not-so-fortunate older people. But when you look at individual cases of how older people have got the top positions you realise that it didn't have anything to do with their age. I was certainly not appointed to my current job at the University of Aberdeen (at the age of 60) because I was old. Really. Neither, (going a long way further up the food chain!) was Vince Cable, the Liberal Democrat Leader, or Jeremy Corbyn, the Leader of the Labour Party appointed to be leaders because they are retiree age. They got these jobs because of their reputation and respect among their relevant party members (or some of them!). Of course being around a long time helps you build up experience and achievements that impresses people, but that does not automatically follow just because you're old! But the fact that you are old can certainly detract from your appeal in many people's eyes.
The third way that society is institutionally ageist is a very obvious one. Calling somebody old is an insult (even though it shouldn't be). The very fact that it IS an insult and is routinely used, often without any reflection, is a mark of the institutionalisation of ageism in the very fabric of modern culture. If you want to insult a politician, call them 'old'. If you don't like the people who voted for Brexit, call them old - now that's really common these days. It's a way of avoiding the argument, of appealing to your base (mainly young people) - it's a reverse of what people attack Trump for doing in fact. I think leaving the EU is a bad move, but it's got nothing to do with the age of the people who tend to like the idea, and everything to do with the arguments about internationalism, peace, fraternity etc.
The fourth way that society is institutionally ageist is the notion that somehow old people are assumed to have a better deal than younger people. Well, some do, some don't. But on average they certainly don't have higher pay. Household income for the over 65s is, despite some improvements in recent years, still only three-quarters of the average younger people. What's so marvellous about that? There's also the not inconsequential fact that the oldies on average have rather fewer years of healthy life ahead of them than the younger people. Yes, there's a lot of problems facing younger people that need sorting ...housing, tuition fees etc etc. But don't take it out on the oldies please.