So, just as I predicted, your question of "What is this?" really wasn't an honest question: you were setting up a spike for your slam dunk on how awful Disney is. There are two plausible reasons why there is an exposed pipe:
1. Like many dark rides, they are set to be seen from only one direction. If you have ever looked backward on a dark ride (go to YouTube for 360 degree videos and look backwards) you will see a lot of behind-the-scenes stuff you don't see from the forward direction, especially a lot of cameras and light sources. That pole looks like it would be hidden by the log in front of it and you really don't see it unless you look backwards.
2. It seems, though I could be wrong, that the Na'vi have reclaimed Earthling refuse by decorating it, especially metal poles with their weavings. There seems to be some of that out in the land in the open. This may be another case in the ride, which means that some of the pole they decorate is exposed on purpose, since native weavings aren't perfectly all encompassing.