Yes, it is wire fraud, a class C felony in the US. You put that there with the intent of extracting $500 from somebody else that they didn't agree to. The mechanism makes no difference.
It probably also violates local laws (including simple theft in my jurisdiction).
You will argue it was consensual. Your HN posting history must be erased before it befones relevant.
You said please give $500 and they gave $500. No crime here, officer.
If you go up to someone on the street and say "give me your wallet" and they give you their wallet, you committed a robbery, even if you made no explicit threat and had no weapon.