Compliment to the derogatory masculine form "tool", which is used to refer to a male with similar qualities. "Tool" as a derogative term is derived from the use of "tool" as a general term for male genitalia. "Toolbox" can easily be construed the feminine equivalent. Tool is to toolbox as penis is to vagina, being the most obvious analogy, "toolbox" becomes an elegant compliment to "tool" in the pantheon of gender-based disparagements.
Yeah, that's a real toolbox.