If Gilead is wicked, Surely they are worthless. In Gilgal they sacrifice bulls. Indeed, their altars are like heaps in the furrows of the field.
"Their altars are as heaps in the furrows of the field ..." This is the judgment, uttered in the prophetic tense.  It is already a fact, as much so as if it had already happened.  All of those altars upon which Israel had lavished wealth and adoration would finally be nothing more than rubble that a farmer had to plow around when working his field.