I don't think it will make us look bad. The fact that he had chemicals to make explosives should overshadow the firearms infractions (I hope).
The weapons he had were prohibited/modified so it's not something that can be faulted on our gun laws. But then again, the average Joe wouldn't know this.
And did I miss something, or was his plan not to kill people but rather destroy equipment and steal data? What was he hoping to accomplish?