As I remember the old episode of The Simpsons, Homer was being chased by a ferocious bull. Just as the bull was closing in on him and he thought that he was going to die, Homer cried out, "Jesus, Muhammad, Buddha...I love you all!"
Homer Simpson's theology reminds me of the theology of the Israelites from the days of the judges until the Babylonian captivity. They never abandoned the true God; they simply added other gods to their worship. (However, God saw it as abandonment, and he was right. By adding other false gods, they had forsaken him in reality. They demonstrated that they did not really trust him.) They attempted to use the Lord when he was needed (to win a war or to produce a crop), but when they perceived that he was failing them, they would turn to other gods in hope that the other gods would give them what they wanted.
I understand that Homer Simpson theology is still a problem in areas where idolatry is common today. Some people may claim to believe in Jesus in India, for example, but they may have only added him to their pantheon of gods, making him another idol to use for selfish reasons.
In America, someone may believe in Christ to some extent, but check the horoscope for direction in daily living rather than the words of Jesus Christ. When we engage in such activity, we are embracing Homer Simpson theology. Christ has simply become another idol to use for our personal benefit. We have rejected him as Lord. Our proclamations of love for him ring hollow. Many more examples of Homer Simpson theology could be cited, but the important thing is to heed the words of the apostle John: "Dear children, keep yourselves from idols" (1 John 5:21, NIV).