It may be subjective and hard to prove but based on your personal experience as user/hiring manager and/or candidate and your analysis,
Do users/hiring managers feel insecure when a more capable (and probably younger) individual apply for a role (in your team/department) AND reject/ignore the job application?*
*Partially to protect the users/hiring managers' best interests (e.g. position)?
Notes:
$ Reject application does not solely mean sending rejection letter/email prior to interviews/selection processes. It can also include final decision to turn the candidate down after a series of interviews/selection processes.
$ I know there can be lots of scenarios and possibilities as to why a candidate does not get the job or why users/hiring managers turn the candidate down (examples would be hiring companies posted vacancy/position which does not actually exist just to expand their talent pool/gauge the labor market/for other purposes, they have (personally-referred) candidates in mind but still advertise as required by the regulations for formality, they interviewed capable candidates to look good and show that the company is professional regardless whether they actually hire the capable candidate vs someone they are feeling (more) secure with, etc.) but let's stick to the question and poll.
A successful manager surrounds themselves with trustworthy people that are experts in what they do. I am delighted when I find a superstar, regardless of how old they are.