Beliefs follow desires, desires don't follow beliefs.
People don't reject God because He is evil. people reject God because everything that God stands for is fundamentally at odds with their own desires. They're incompatible. People just tend to define things that are at odds with their own thoughts and desires as "evil" (e.g. racists don't believe racism is evil, they see it as personally reasonable and justified). Accepting God requires the rejection and subjection of your own thoughts and desires. If you accept God, then you will merely accept the fact that you don't understand or can't explain why God does everything that He does. It's not a big deal. The question of whether God is evil or not only makes sense for someone whose desires are at odds with God.
There's also the unspoken third position of apathy. For many people, questions about God and His nature just aren't important enough (i.e. don't impact their day-to-day lives enough) to be worth serious consideration. Many of these people may choose to believe God, if He exists, is good merely because it's comforting and/or convenient. For these people, as long as the question of God doesn't interfere with their day-to-day desires, they're content to remain apathetic on the matter.
Practically every decision people make is based on a gut instinct or feeling that is either positive or negative. People follow the positive feelings and reject the negative ones. It's this simple dynamic that shapes practically every aspect of people's lives, from their simple likes and dislikes to their politics, sexuality, religion, etc. It's these feelings that shape our beliefs as well. People have drastic changes in their lives when, for whatever reason, the positives and negatives are reversed. This might be caused by a sudden change or increase in cognitive dissonance or a sudden revelation of new information. For Christians it's often the personal experience of encountering God or the revelation of their own sinfulness or reaching a point of desperation in their lives (or all of the above).
It takes a serious internal struggle to accept a belief that goes 180 degrees contrary to your personal feelings or conviction on a matter.
PS. Sorry if this is a bit rambling or off-topic. Take it for what you will.