@nprofile1q...If you see someone being picked on, and you are in* a position to be noticed, you call it out.
Even if you don't change the behaviour of others, that person knows that *you* have their back. Which is much better than feeling like you are completely alone.
As for recruitment, where I am we do name-blind recruitment where we don't know names or ages until they accept an interview and then we make sure that interview panels are diverse, that our first questions are consistent, that everyone is aware of the criteria and that we have review meetings to make sure everyone can share opinions on interviewees. Its not perfect but no process ever will.
*edit: heatwave brain can't english