1 Referee and 2 linesmen who are responsible for keeping track of 22 players, and a ball all of whom are moving at a high rate of speed. Thus, I can see certain mistakes, like the German handball in 2002 as it was a pile of folks in the goal box. But, the obvious and controversial gaffs are just not excusable such as the missed goal by England in 2010 or the guy from Croatia getting 3 yellow cards and still not ejected against Australia in 2006. FIFA needs replay technology, especially in goal situations where the ball stops anyway; but, Sepp and company want nothing to do with it. There has even been talk of adding a second ref; but, politically, that is dead.
That’s why many soccer fans will start singing 3 blind mice when things get bad, even at the youth level. I played a soccer JV game once against a ref who was running around with the ref’s handbook open in his hand. Played a varsity game against one team in which my team picked-up 7 or so yellow cards (2 ejections) while the other team received none in a very physical match. Found out later the referee was the brother of the other team’s coach. That did not go well with the high school sports council. I went to a girl’s county championship last year between the top 2 teams in the state in front of 2,000 people go into a second (and last OT) tied 1 to 1 in extra time with the scoreboard clock blow the game dead during a 1 v goalkeeper breakaway. I am a ref, also, and could not find any excuse for that call.