As usual, people see what they want to see, then complain when the facts ain't what they want them to be.
The receiver is airborne when he gets the ball in his hands, then one foot lands in the field of play, and then the second foot lands on the sideline. All the while the receiver is falling backward to the ground. He must maintain control of the ball during the entire process of the catch. As bad of an angle as this video is, you can still see the ball bobbling - not just moving slightly - as his foot touches the sideline, and as he is falling to the ground. This is not a catch. Incomplete pass. Nice athletic action, but not a catch, by rule.
Oh, replay changed it from a TD to an incomplete pass. Shocking.
A far cry from backpedaling three steps after getting firm control of the ball, then stumbling and falling to the ground.
Not always, football officials see what they believe their eyes tell them, which at times, may not be as complete and accurate and informative as what multiple camera angles, that can be manipulated at multiple and different speeds are able to record. Which is the reason there is IR review (at levels of the game above the NFHS level).
A principal benefit of IR, from a training perspective, is that it allows officials to review the benefit of certain perspectives gained from proper positioning, not being too close, or too far, making sure that the area you may be assessing from is not congested with unauthorized spectators, focusing on what you need to be observing while avoiding unnecessary congestion and of course knowing what, specifically, you should be focusing on (as quidded by the appropriate rule).
We base our judgments on what we SEE, rather than what we think (assume, suspect, etc.) might appear to have happened. Everything we see happens at a single speed, in "real time". Camera views can move closer (after the fact) and often change angles and views to move around congestion that may block a complete view, at a variety of angles.
Vince Lombardi suggested, "Perfection is NOT attainable, but if we chase perfection we can catch excellence", which is what IR is capable of accomplishing, but even that remains short of consistent and absolute perfection. Using film and cameras is a valuable tool in helping the chase of excellence, by demonstrating the impact and importance of pursuing and applying learned and effective practices, but the individual human observation is not likely EVER to match the continuing progress of multiple camera observations, which are far more likely to continue improving.