Odin hung from the World's Tree
Moses and the caduceus
Christ on the Cross
Ixion on the Solar Wheel
The Sun God in the middle of the Solar Wheel
The Tree and the Cross are the same symbol.
The only problem is those who wear it thinking that some external savior is going to make their wrong-doings vanish (until of course they do wrong again). If they use that symbol to remind themselves of the constant journey of the Self to uphold Truth then more power to them. It IS a symbol of sacrifice like Sunny said, one must take up their cross daily, that is walk the path of Truth, and again like Sunny said people will throw stones at you for doing that because it shines the light of Truth back in their face.