I have severely inverted nipples, therefore couldn't breastfeed my children. (I could have expressed in an attempt to establish supply, but it would have been a full time job during the time I should have been bonding with my babies, and it may not even have worked). It was immensely upsetting at the time, and even now eleven years on I still feel pangs of sadness, guilt, jealousy and inadequacy when I see breastfeeding content. I suppose if I still feel this way this far down the line, I always will.
I try not to begrudge people posting breastfeeding content as we're all adults. But by the same token, I've never posted about how proud and happy I was to give birth without intervention or pain relief, because a) it's largely down to dumb luck how these things turn out and b) I would never want someone who didn't have the birth experience they wanted to see it and feel sad. It's not worth it for me.
I think it's worth noting that in previous discussions around posting etiquette, I've had quite hostile pushback when I've stated my views and my MO. My bottom line is each to their own re: what to share; but I personally try not to share anything that could potentially cause pain