Why is AG Gonzales NOT being impeached?

That doesn’t matter. Impeachment was deliberately designed to be a political process separate from the criminal process. Nixon v. United States, 506 U.S. 224 (1993). An impeachment and conviction is absolutely unreviewable by any court. All it takes it the political will to do so.

From Salon:

In answer to the OP: Because the Senate can’t even muster enough votes to break a filibuster on a symbolic vote of no confidence. Impeachment? It is to laugh.