No. An empty cross made of railroad ties and left lying across a rock is a passive, nonviolent and non-threatening symbol. This one could easily be removed without damage to the area or anyone. While there have been Christians who were threatening toward pagans, there is no reason to assume that Christianity is a danger to any pagan today.
The swastika is only associated with the Nazi Party which perpetrated the Holocaust. If it were to be “thrown” as a piece of cloth, it would not damage the area or anyone physically, but there is no way to associate it with anything other than an attempt to annihilate Jews.
Would you be writing this to Christians who found a wooden Islamic crescent hanging from their church pulpit?
It’s a passive, non-violent and non-threatening symbol. One that could easily be removed without damage to the area or anyone...