Earlier quoted context omitted.
How could it possibly be relevant to your hiring decision how old someone is, or what neighborhood they live in?
You can guess someone's age within a few years at an interview if you wanted to discriminate, so blocking a mention of age is naive. You could also work it out in most cases from the dates given on the resume (unless it becomes illegal to learn about a candidate's education or work history - which wouldn't surprise me to be honest). You could see what neighborhood someone lives in because that will also be typically…
Isn't every question optional? It's not like you go to jail if you don't answer a question. It's not a good strategy, but AFAIK it is legal