Far be it from me to defend the government ... but in this case, the fence and gates are there for two purposes, neither nasty.
The fencing segments the forest for cattle grazing. Different ranchers get rights to put their cattle on different sections.
The gates are closed to some roads over the winter to keep people from getting their vehicles stuck in snow and mud, and also to keep 4WD from tearing up the forest roads when their muddy and wet. Those gates and roads will be open soon. Not sure when, but I think May 1 at latest.
You're totally free to walk in.