At least in the case of trademarks, the potential for defamation gives it some credibility. I suppose from the standpoint of brand confusion alone, trademarks and patents are both equally unethical in that they both do not recognize independent discovery. Copyright is a much more balanced approach imo. Frankly I don't think many in many industries have the balls to admit just how much they would dislike their natural rights trampled on. In my experience, any time the conversation heads in that direction, the affected parties are seen scurrying away. For instance, I reckon a lawyer would reject any notion of limiting their natural right to practice law? Or perhaps even just certain techniques thereof. Really, I think it's time we start carving up territory in the domain of legal tools and tactics. Heck, I say we start carving up territory in just about anything one can think of. At least then the ridiculousness of it all might become apparent to enough weighty makers, that they would see to it that it'd be changed.

There are two issues here: whether a given law is ethical or not as written, and whether the spirit of the law can be supported even if it is unethical as written.

As it turns out, one can make an argument that copyrights/trademarks can be reformed, but patents cannot. The difference is that no one can accidentally "trip" over a sensibly defined copyright or trademark, whereas patents are intrinsically a legal landmine -- people can and often do accidentally infringe.