It seems to have great significance to some. I think it's related to wide-spread usage of cross as symbol for christians. It's symbol on churches and people use it as jewelry among others. If the tree was cross there is relation to why this symbol could be used and the declaring it pagan symbol would lose ground. One way of proving you are right is the prove others are wrong, "there, you see, they even use pagan symbol to describe themselves, how low can they go", kind of logic. Those fake-christians use pagan sign as their most significant symbol, they are so evil and drifted away from true religion, right. It sounds less convincing when you must state that for some reason they want to use the murderweapon as their symbol, but it really was there and is related to death of Jesus.
Semantics, I would say from my point of view, but the devil lies in nuances.
CP