Why? The grandparent is not saying it's coincidence. Why is it not okay to hire someone who has a voice similar to celebrity X who you intentionally want to immitate? I mean if you don't actually mislead people to believe that your immitation is actually X - which would be obviously problematic?
I don't believe Sam Altman, but I am interested in the general “is it legal/ethical to immitate something uncopyrightable” argument.
(Can't for the life of me recall if she sounds anything like Johansson; just putting her forward to tease her relative here. (Who is in the wrong in his arguments above.))