I have to agree that your paragraphs do seem to contradict. What you describe in the first paragraph is how you control the road to ensure that those wishing to pass you do so safely...basically it seems that you agree with taking the lane in this context.
The only difference I can see in what you are saying, and forgive me if I have this wrong, is that you initially take the lane and if the driver behind waits patiently you stay there. However, if the driver behind starts revving, beeping, etc then you swing over into the gutter and allow an impatient and bad tempered driver to overtake where you have already decided that it is not safe to overtake. I would not do this, rather I would continue to block the unsafe overtake until I deemed it safe to let the driver past....I certainly don't want such a driver trying to squeeze past me in an unsafe situation.
If, on the other hand, I'm riding along on a road, in secondary, where it is safe for drivers to over take me, then I will happily stay in secondary all day (apart from at junctions, etc) and let them past. I know of very very few riders who actually ride in primary just to hold up traffic, rather than to benefit their own safety. Likewise, off the top of my head I know of no cases where riding in primary has led to a collision...assuming that it is done correctly.
But it does occur to me that if drivers know that revving their engines and banging their horns will make some cyclists swing over into the gutter and let them squeeze past, then they will be more likely to do it to all cyclists and become even more bad tempered should said cyclist not immediately grovel in the gutter for them.