The Illuminati themselves weren't sinister or even elitist, they simply resisted the church's teachings and favored science over religion. The reason many believe they are in control is that there is symbolism everywhere, particularly in America, of Freemasonry and the two movements were related, but not identical.
There is nothing truly sinister about Freemasonry either.
Are there people in control of the world in the background? Perhaps. Are they the illuminati? No. They are most likely the 1 percent of the riches one percent.