[ApplegateRanch]

I can think of a lot of reasons. They might not want criminals to know their real name.

I would assume that "identify" would mean showing ones credential, not verbally giving name, address, and phone number. That is a routine and expected action; and the reason cops carry an official ID.

[driftdiver]

Yep, when a cop won’t prove he’s a cop then he’s not a cop.

In this context show a badge or something else to prove you’re real.