Illuminati just means 'enlightened'.
Flip the dollar bill. What you will see is the eye of Horus, with the Sun on it (since Horus was the sun God), with an Egyptian pyramid, that has 13 layers (one sun and 12 zodiac signs, personified with Horus and his 12 disciples), and roman numerals at the bottom which are 1776. At the top it reads Annuit cœptis which means undertaking approved, referring to the establishment of Christianity, to unite the masses under a new world order. The other side of the seal is borrowed directly from the winged sun of Thebes, ancient Egypt. At the top there are 13 stars on top of a sun, circled with clouds, with a latin phrase e pluribus unum (one out of many), in this case, Jesus, who was one out many other "sons of God" (Mithras, Horus, Krishna, etc)..
So why are they called devil worshipers? In the past, there were mystery schools which taught some people the truth about Christianity and its astrotheological origins. Those that knew were known as the illuminati, or enlightened ones. Today, when you mention the astrotheological origins of Christianity, you're automatically labeled as a devil worshiper.