Many times judges are criticized for issuing a sentence the public thinks is too light, or because an acquittal is the verdict in a high profile case. But the public that blasts "activist judges" often, I think, reaches a verdict based on their perceptions (largely arrived at based on media coverage and pre-conceived notions of justice) as opposed to any access they would have had to the evidence, or their knowledge of law.
While I agree that many legislators at the federal level have a knowledge of the law, or are lawyers themselves, most crimes are state ones, and state legislators are much more often laymen. Mine, for example, is an apple orchardist with no legal experience. Nice guy and all, just not the one I would want in the position of tying the hands of a judge with actual, long term legal experience. I just find legislative bodies to be much more reactionary than judges, because they have to be accountable to the popular will whether or not that will is rational or well informed.
I understand your point, I just think we're coming at this issue from different angles.