over 3 years ago - Shurenai - Direct link
On the one hand, I see where you're coming from. On the other, it's fitting to the world, and also from a player interaction/experience perspective.

'Red' is a sign of danger, It makes it patently obvious to not walk into the bloody red spike; Without that obvious sign of danger, Believe me, There would be multiple (if not many thousands, certainly much more than one.) people who wouldn't immediately make the connection of 'spikes hurt', instead considering it a decorative item until they walk into it like a dummy, or a zombie happens to do it in front of them before they do it to themselves.

But also, and this is more likely the central reason as to why it starts bloody, is that the spikes are universal- There is one 'Wooden Spike' asset with several damage states. The wooden spike you build with is the same one used in building POI's in the world where, concievably, zombies would have been damaged or died upon it in the past. World building > Silly inconsistency of crafting a bloodied wooden spike.