I think you're wrong in ways that are difficult to untangle. To give an example of an obviously flawed deontology, "Never swim within 30 minutes after eating"

I think you're wrong in ways that are difficult to untangle. To give an example of an obviously flawed deontology, "Never swim within 30 minutes after eating" is a deontological rule. Many experienced swimmers (or eaters) know that this is a rule that can be broken safely, and choose not to follow it. Not to say that better or more complicated rules don't exist. The 10 Commandments are a deontological system, and are not identical to consequentialism. The contrast is- following pre-established rules, which were (hopefully) written with good outcomes in mind, vs. judging the likelihood of good outcomes on-the-fly.