I was referring to things that are illegal (murder, kidnapping, assault, theft etc.),because they severely harm the life, limb, or property of others. I was pointing out that just because our laws against these crimes do not stop every instance, there is no reason to abolish the law itself.

You're talking about things which have a wide variety of perfectly legitimate uses which we (quite properly) allow in spite of the fact that they can, on occasion, be used to harm. This is obviously and substantially different.

Indeed, when you think about it, these very different things are nevertheless complementary. We allow potentially dangerous things to exist because we're (reasonably) well-assured that any truly harmful applications can be dealt with using the laws we reserve for handling grievous harms.

Regarding the "example" you brought up, the difference between robbery and pot is that pot is actually quite popular and the war against it is being waged with profound incompetence and for reasons that are increasingly suspect. Robbery, on the other hand, is - and remains - widely unwelcome in nearly any setting, even among thieves.

I'll do you the favor of assuming you're actually intelligent enough to grasp all this and that you're simply trolling. God help you if you're stupid enough for these distinctions to be truly baffling.