Most of you people are looking at this from an Athiest's standpoint. Saying things like, "Does it make them wrong that they worshiped multiple Gods vs. One God?" People with faith have this mindset: My religion is right. If you expect a person with truly devout faith to say, "Well, I might be wrong", then it won't happen, because that defeats the purpose of faith. I'm a devout Christian, and I believe Christ will be coming back soon. And when he does, un-Christian's will basically be tossed into Hell, and the Christians live on His kingdom on Earth and are in Heaven. It may not be what you believe, and that's fine. But don't expect me to say, "That MIGHT Be what's going to happen", because if I said it might not, that'd be like saying, "I'm not sure of my religion", and I'm quite sure of that.
As for the evidence of Jesus' existance: The Shroud of Turin may (or may not, they don't have any definitely proof yet, mostly speculation and forsensic evidence) that it was the shroud that Jesus was wrapped in when he was buried. It has bloodstains that show crucifixation and a crown of thorns, as well as the spear wound Jesus was given to assure he was dead on the cross. There is other evidence as well, but all I'm going to say any more about Jesus' existance is this: Faith means I don't need evidence. I've felt God in me, and I believe in him whole-heartedly. So, even if there was absolutely zero evidence of Jesus, I would still believe in him just as strongly.
Also...as for Him hating the cross. The cross doesn't represent His crucifixion, it represents the salvation He granted us. So, I think that's why it's a symbol.