Part of the mythology of Jesus is that he got better. So, the cross became a symbol of his sacrifice and suffering for the followers of his religion. It’s a constant reminder of “look what you made Jehovah do by being an evil sinner.” It is also a concise icon which can be used to identify the members of the religion. And, it’s been in use for a long time now and is well recognized as a Christian religious symbol, with the original usage of crosses as torture and execution devices being mostly ignored. Perhaps back 1500 to 2000 years ago, such confusion may have made sense. These days, it’s so far removed from that context that such confusion is usually a matter of being willfully obtuse.