PC "Back story", why is that a thing?

[OldTrees1]

Do you notice how very few words described what they did in the past? It's all about who they are not were!
As a DM I am much more impressed with a description than a history!
To those who demand a history as an audition?

As I said before there are at least 2 philosophies on what the question "Who are you?" entails. Both are viable and valid. Having a personal preference as a DM and requesting your Players answer the question as you mean it is perfectly acceptable and normal. Just as you being more impressed with the description(to use your language) is acceptable, so to another DM's being more impressed with the history(again, to use your language) is acceptable.

I have suggested that you personally filter for like minded groups when looking for a group since your preference is so strong. Asking the DM "Who are you?" should give you a good idea (except possibly if they are Babylon 5 fans ).