I don't think all games are fixed or "manipulated" by the refs, but to think it never happens, well, that's just not very sensible.
I watched a game last year between the Eagles & Cardinals in Philly.
Close game up until the 4th quarter, but then the refs took over....Seemingly determined to not let the Eagles lose
There was this one play that was

...There was like 4 mins left in the game and the Eagles were up 3 and had the ball on their own 35 yard line.The Cardinals send a blitz and get to Foles...He's basically wrapped up & sacked/inches from the ground and just throws the ball up for grabs...the ball fluttered about 5 yards in the air, barely making it past the line of scrimmage, and was picked off in the middle of the field by Patrick Peterson.
Peterson's running with the ball when a late flag comes in.....Pass Interference on the Cardinals.They called it on the other side of the field.The side Foles wasn't even attempting to throw the ball to.Foles wasn't throwing the ball to anyboy, he was just trying to avoid the sack.
I can't even explain that shyt...it was one of the biggest bullshyt calls i've seen in the last 5-6 years