This is probably a better question for /r/judaism, but now that it's here...

It's not a religious symbol of Judaism at all. The only reason it is a symbol is because of Jesus' crucifixion, which has no theological relevance for Judaism (except what people believe about it). So there's no reason why it would be relevant.

Leo Rosten suggested that the slur for Jews, "kike", originated in the custom of illiterate-in-English Jews signing things with a circle, rather than an x. While his etymology is a bit unsupported, it indicates that there would've been an aversion to it as another religion's symbol.