That's great, that you can copy/paste US Code, but the problem is without looking how the Courts interpret that law, you are making aimless conjecture.
The DOJ under Ashcroft had tried to take down Greenpeace before in a similar case, and unsurprisingly they didn't even attempt to use the code you cited. Why not? Because the government had to admit Greenpeace's activity was peaceful. Free speech always trumps overbroad laws (which the cited code would certainly be if hostility were to include non-violent protest, it might also strike out for vagueness). And as to the disposition of the case, I'll let you read up on that.
http://en.wikipedia.org/wiki/Sailormongering
http://www.commondreams.org/headlines04/0520-12.htm