If a criminal goes into a 7/11 and blows away the clerk and it’s caught on the security camera, that video can’t be used against the killer?
Good point.
In a murder case, however, that probably wouldn't be sufficient evidence to establish guilt beyond a reasonable doubt.
Video footage could be used as evidence that the crime was committed by the accused, but it would typically be accompanied by additional evidence.
Most murder cases I'm aware of involve one or more witnesses, whether they be eyewitnesses to the crime, or at least expert witnesses that testify about forensic evidence, video evidence, etc., and the defense has the opportunity to cross examine all such witnesses.
Again, with the red light camera, it's just the human vs. the machine, with no witnesses of any kind available to directly examine or cross-examine. It just doesn't seem proper to me.
This is probably the reason that many (most? all?) red-light camera cases get dismissed when the defendant actually seeks redress in court by pleading "not guilty". The powers that be rely on the fact that most people simply don't want to go through the hassle of fighting a traffic case—even one they would likely win!