I can only guess you have watched football for a very short period of time. Do you think all the games in the 70s, 80s, 90s where called perfectly and there was never a controversy? Back then we got one or two replays from the network during the game and that was it. No one at home watching a replay on DVD over and over, analyzing every play to nearest inch, no 24 hour ESPN fanning the flames, no Internet analysts looking for something to write about.
Yes there were LOTS of blown calls. They just weren't analyzed to death.
The games are fixed? Have ever thought how many people would have to be involved in that?? Do you really think the NFL would risk destroying its reputation so Pittsburgh would win a regular season game over Miami?