I would be very concerned about a work environment that clearly lacked diversity. At best it would not be a very interesting place to work, but mostly it would indicate some inherent managerial problems .
As for people saying the 'best' candidate should get the job, they have clearly no idea how to hire people and build effective teams. There is no such thing as best. There are dozens of dimensions to qualify people on, and all you can tell in interviews are rough estimates. Everyone has strengths and weakness. The goal is to find someone who can function in their role and can strengthen the team. Diversity is well proven to improve team performance , so that trait alone adds huge value if your team is not already diverse. You should never be ranking candidates as that can lead to all kinds of biases and leads to selection on criteria that are not actually useful to the company or team.
As for people saying the 'best' candidate should get the job, they have clearly no idea how to hire people and build effective teams. There is no such thing as best. There are dozens of dimensions to qualify people on, and all you can tell in interviews are rough estimates. Everyone has strengths and weakness. The goal is to find someone who can function in their role and can strengthen the team. Diversity is well proven to improve team performance , so that trait alone adds huge value if your team is not already diverse. You should never be ranking candidates as that can lead to all kinds of biases and leads to selection on criteria that are not actually useful to the company or team.