I am really not sure that the no-holds-barred AIBU topic is necessarily the best place for a reasonable debate about this, but there's some fascinating stuff on this thread all the same.
Those who already know me will be aware that I am absolutely not interested in forcing women who don't want to breastfeed to do it; my aim is to influence those who can do something about it (those who hold public purse strings, for instance) to put breastfeeding support on the agenda. I have been, imo, rather successful at that (more on that soon).
Those who don't know me - well, read the last paragraph! 
And by breastfeeding support, I don't mean lots of breastfeeding nazis (are we STILL using that? Can we use "judgy-smugger" instead, please? Look, here's why!) judgy-smuggers sitting in a room, wearing woven lentils and looking disparagingly at other women. I mean more sensitive language, more understanding of, ahem, how breastfeeding works, why it is important (and it is, you know - if it isn't, why are so many people posting so angrily about it?), more empathy, more consistent information and far less myth and misinformation.
My ultimate aim is for any woman who wants to breastfeed to be able to do it for as long as she wants. And yes, some of the women who want to will be unable to, some for physiological reasons and others for reasons of circumstance (though if bf were recognised as important in wider society, many of those circumstances would melt away) - and that is also something that, with the right support, the right language and the right approach can be managed so that nobody is left distraught or feeling guilty.
Because - guilty? For wanting to do something for your baby, but being let down by those who should've supported you? Those who should've known better, BEEN better? I would heartily suggest you get angry, not guilty. Be sad, by all means - absolutely. It IS sad when you can't do something you want to do for your baby. But guilty won't help you and it won't help those who come after you. Angry will - angry with those who didn't help you when you needed it most. Tell people how important breastfeeding was to you, how let down you felt, how desperate you were to do it (if you were - and many women are), how sad you were when it didn't work and nobody helped you.
And maybe if we can all get bf higher up the agenda, then it won't matter how other women feed their babies, because they'll be feeding them the way they want to. At the moment, it matters - it really matters. Or there wouldn't be nearly 300 posts on this thread (and x zillion other threads like it).