GitHub is there so you can present your code to the world in an organised, documented, and personalised way. Part of that includes a short bio and profile pic. I don’t expect a professionally framed headshot with nice lighting, just upload something that’s not the default, to set yourself slightly apart from the crowd.
It’s not unreasonable to expect a candidate to groom their public profile before using it as part of a job application. If they have some bad, old code they’re not proud of, why not make it private temporarily?