The law would have made it illegal to film police officers within 8 feet of law enforcement activity if the officer had requested the citizen or journalist to stop filming. In addition, officers could have ordered anyone filming on public property to stop if they determined the area was unsafe or if the person filming was interfering.
It’s already illegal to interfere. This is to prevent people from holding the police accountable. Let’s say you see 10 white police officers beating a black man while calling him the N word. You whip out your phone and hit record.
A police officer stops what he’s doing and walks to you. You’re now within 8 feet of the officer so you need to either stop recording or go back. If you stop recording, the police have successfully stopped you from documenting what they were doing despite you not actually interfering with police business.
If you keep recording and walk back, though, the officer keeps advancing. By the time he stops and lets you keep recording, you can’t see anything that is happening. Your recording is now useless.
Alternatively, since you were recording before you backed up, you might have broken the law and now can be arrested by the officer. He confiscates your phone as evidence. If you’re released and given the phone back, it’s been wiped clean (or just smashed to bits).
It’s not about keeping people from interfering with the police. It’s about keeping people from keeping the police from abusing their power.