Some blogger named Melissa Fong gave an interesting perspective on the letter thing.
I saw an extraordinary amount of traffic coming from this thread to my blog and was interested in seeing the discussion. I'd like to guide people to Jezebel: http://jezebel.com/the-problem-with-all-these-half-naked-pop-stars-is-th...
The gist of the post is that there are a lot of things to criticize and slut-shaming, which is something I feel Sinead did in spades, is NOT one of the things we should be supporting: http://melissafong.wordpress.com/2013/10/04/sinead-oconnor-likes-to-slut... (I wrote that post just after the first one that mark_alfred linked.
Also, @Timebandit : You may disagree with my point of view and critique it as undersupported. But assessing that I haven't tought about the big picture re: sexism and capitalism due to my youth is incredilby condescending.