The rap I most often see on criminal defense lawyers is that they defend people whom they know to be guilty, and that this makes them amoral at best. Do you have a view on the profession and on this particular "How can you defend people who ...?" question?
I did some criminal defense work at a low level as a young attorney-mainly stuff like DUI or other misdemeanor offenses. When i was with the DOJ I often dealt with defense attorneys-mainly in appellate matters or post appeal motion practice such as 2255 petitions that prisoners file as a collateral attack upon sentence. The system works only if both sides are competently represented. The accused has the absolute right to make the state or federal government prove its case beyond a reasonable doubt and that best happens with zealous and competent defense counsel. And it is -in my view-perfectly honest for a defense attorney to believe his client is guilty but the state cannot meet it's burden and if that is the case, acquittal is the proper verdict.