Refusing someone a job because of their age is illegal in some countries. In my opinion, this development is positive because, there can be discrimination if job owners refuse to give a job for elders.
On the other hand, the position of the business owners is understandable. The cause of it is, the rising number of younger people who is more energetic and enthusiastic to their work and if the job owner had a chance to choose either younger person or elder, owner would more likely to choose younger in order to had the work done well and on time. In the job which requires more physical activities rather than intellectual ones, majority of workers are in young ages who can work fast and in this working process most of the elders cannot attend due to their frequent problems related to their health.
However, firstly, if older people have intellectual abilities and enough skills, high school diploma or even experience to get the job which they want, the job owner must give a chance to show his skills in that field. For instance, in the field of teaching or health, elders have to be welcomed and accepted to work easily, if they have a diploma. Secondly, in some countries there is also considered to be pension for elderly, but it can be too low to live in expensive metropolises, so people have to work to have extra money. In these cases, it can be difficult to find a job, and by making it illegal to reject giving the job considering only age is very effective for older generation.
In conclusion, personally, this rule has to be made not for all type of jobs, but considering all factors and making it for some of the jobs can be fair for both elders and also job owners.