I think FB takes it easy on pages by making people take a few clicks to unlike a page. Its in FB's best interest to have pages build up engaged communities, so they probably have it set this way to cut down on unlikes. However, if pages are annoying or boring, nothing will keep me from that Unlike button.
I think you bring up an interesting point and Facebook should make it easier to express neg. feedback and report to community managers thoroughly on the stats. It will only help us all get better!