Yes, the 'breastfeeding mafia' can be very cruel and judgemental.
My first baby was born by emergency section after a traumatic labour, and my milk did not come in at all. I was told that this was because at times of trauma the body closes down a step at a time, and milk production would be one of the first things to stop, as it wasn't essential to my survival.
Anyway, I bottle fed, and my baby was/is just fine, and very heathy. At an NCT party when he was about 3 months old, and I was still very hormonal, I overheard the teacher saying to another friend that if her baby died of SIDS, at least she would know that she had done her best by breastfeeding. I was devastated, and still haven't forgiven her, even though I now accept that it was thoughtless rather than deliberately nasty.
Everyone there knew about my circumstances, but they were so wedded to the notion of 'breast is best' that they didn't stop to think, and nobody said a word.