Purple - it wasn't me who quoted '5 per cent cannot breastfeed for medical reasons'. So I can't provide a reference :)
I don't know what the 'real' figure would be, anyway. It could only ever be a guess. If you mean 'cannot produce any breastmilk at all' the figure would approach zero. If you mean 'have serious difficulty making sufficient milk to breastfeed exclusively for several months' then that's a different matter - and even then this would mean assessing the baby, too (because some babies are harder to feed than others).
Papers supporting breastfeeding (what does that mean?) are always criticised on forums - what have you been reading?!
The paper I referred to as being rubbished was nothing to do with doubting breastfeeding 'benefits' - the 'doubting' was all froth and commentary. The science of it was rubbished, and rightly so.
I agree that sometimes, the emotions and personal experiences of people get in the way of discussion, but that does not mean it is difficult to assess claims...as long as people know a bit about scientific method. It's no good if someone comes along (as they often do n forums) saying 'I did X and such-and-such happened therefore the research is wrong'.
You will be aware that confusing correlation for cause is a no-no - which is why observational infant feeding research has to control for various factors to avoid this confusion. The links with intelligence and obesity particularly need careful scientific analysis to avoid this - and there is plenty of good research that emerges with plausible conclusions. Obviously feeding method is not the only factor in intelligence and obesity! And equally obviously, infant feeding method is not a predictor in individual babies.
I say 'obviously', but I can only think it's not obvious to all!
Your feelings of guilt could be revisited as 'disappointment' and 'sadness'. Clearly, it was not your 'fault' breastfeeding was not a good experience for you or your baby - no need for guilt!
Trying to tell yourself it doesn't matter all that much anyway does not stop you feeling sad that something you wanted so very much to do, and which you recognised as worthwhile and life-enriching , was not to be. There are many things which make us feel sad in our parenting, many experiences that leave us feeling bereft. They matter - but they don't ruin anything, and they are not the be-all and end-all of our relationship with our children.