Football as a whole because there is pretty much 12 players on each team doing their own thing for 7 seconds at a time, and at any point any of those 24 can be doing something infraction worthy because almost everyone one is doing something that contributes to one thing specifically makes it really tedious to replay and challenge things... in that it is pretty unique compared to something like Hockey or even Soccer which has a similar amount of players on the field. Football kind of makes it harder on itself because I don't think any one can tell you everything that can go into making a completed catch sometimes... it feels like the meme for a balk sometimes. You have to make a football move... it can't touch the ground, unless you have control of it I guess? You have to survive contact with the ground... most of the time.
I think that Refs are acting to the best of their abilities in the best interest of the game. If there is something that can be seen at full speed on a camera angle, for sure overturn it. When you start zooming in, and slowing down and dissecting frames like it is the Zapruder film is where things start to fall apart for me.