A robocall is a call made from a number that is reported as illegal
Lots to unpack there.
Robocalls are not illegal. If they were, dentists would be in prison.
Spoofing is not illegal. If it was, law enforcement agencies working cases, victims of domestic abuse and doctors discussing private medical matters would be in prison.
How does a number become "illegal?"
Under the Truth in Caller ID Act, the FCC prohibits "...any misleading or inaccurate caller ID information with the intent to defraud, cause harm or wrongly obtain anything of value."
If no harm is intended or caused, spoofing is not illegal. However, if you don't answer the call or just block the number, you can't prove intended harm.
Spoofing from your local exchange(s) (Area Code & LATA) is the latest ploy to get you to answer the phone. Nomo won't block these numbers because the scammers use your local numbers once and move on to another local number. Blocking these "disposable" numbers would be blocking ghosts...not to mention legitimate subscribers.
Your only defense would be a call-blocking device featuring wildcards. For example, block everything from (123) 456-****. If your neighbor shares your exchange, you could permit their number on the device.