Funny thing is, motorists do the exact same things as cyclists. Yet, when a motorist does it, it is a bad driver. When a cyclist does it, it is a generalization that applies to all cyclists. (I will thank you for moderating your views to a massive percentage of cyclists. Yet your moderation is highly unusual.)
As for cyclist lane usage behavior, I'm not sure what the circumstances are in your city. In mine, the cyclist is to stay as far right as it is safe to be. This means that a cyclist has the right to take the lane for reasons of safety. If you're making a left turn, it is far safer to take the left turning lane to prevent cars from passing you while making the turn. If you're stopped at an intersection, it is far safer to take the right lane to prevent cars from making a right turn across your path. There are all sorts of rules of thumb like that which make life safer for cyclists and have very little impact upon motorists. (Seriously, we are talking about a 5 second delay in most of those cases.)
I have noticed motorists get impatient when I take the lane, presumably because they don't understand why. But if you think about it from the perspective of two motorists, it should make sense. For example, would you want a car passing your car from the left to make a right turn? I'm guessing the answer is no.