I certainly welcome the decision in favour of the discrimination case against Asda brought by a dementia sufferer who was encouraged to retire. But the trouble is that this case also condemns ageist attitudes that dominate society which implictly argues that older people can't do their jobs as well as younger people and that they should be encouraged to retire to make way for them.
Now of course if somebody cannot do their job up to the required standards then they should be asked (and given all reasonable support, including disability support) to do better. Ultimately if that does not prove possible, standard disciplinary procedures should be applied. If absolutely necessary, they should be fired just as much as somebody younger should be fired if they cannot do the job up to expected standards. But such a process should be independent of their age. In the past before the 65-year default retirement was abolished people were literally shown the door at that age (or 'encouraged' to retire earlier), often as a form of cost-reduction.
Obviously it is cheaper to hire a newbee than to employ somebody at the top of a payscale, and you can still hear people even on the left arguing in favour of the now (ostensibly) abandoned policy with phrases such as 'giver youth a chance'. But the left is keen to oppose employers who have tried to deploy economic arguments against protecting women giving birth, or acted in a racist or homophobic/transphobic way, and the 'youth first' argument is no less discriminatory than sexist and racist tropes of the past. The political right meanwhile, have historically tended to be slow to protect people against discrimination.
The trouble is that there's often a lot of political rhetoric against 'old' people at the top. If some leader is unpopular and they are getting on in years, you can bet your life that somebody will argue that part of what's wrong with them is that they are 'old'. It is done because it resonates with many people's prejudices, prejudices that are so taken for granted that such tropes go unquestioned most of the time.
Yet of course the people who suffer most from this type of discourse are the ordinary, often quite poor, older people struggling to find a job. They may be in their fifties/sixties or do not have much of an occupational pension, but are often only hired when the employer cannot find anyone young. At this point people start arguing 'but give young people a chance'. Of course they should be given a chance, but on the basis of their fit for the job regardless of their age. Sometimes, indeed young people are actually passed over because they are too young - that is also indefensible.
Ageism needs to be fought with as much vigour as racism and sexism. Period.