A lot of militant breastfeeders do themselves and their cause no favours imo.
Ultimately it is nobody else's business how someone chooses to feed their baby.
Research shows that it is best for children to be brought up by a parent until they are three, but can you imagine if sahms started coming on to threads saying that women who work don't get enough support to sahm/that women choosing to work and leave their babies in nurseries are selfish/that more women should be encouraged to stay at home etc etc?
Ultimately there are lots of things that are best for children. But none of us, no not one of us, is able to always do the scientifically proven best for our child, either through choice or through necessity. And providing that people aren't doing actual harm to their children, how they choose to bring them up, be that to bf/ff, to wean at 4/6 months, to go to work/sahm, it is nobody else's concern but theirs.
And let's be honest - we're generally only talking about the first few months of a baby's life here. If you take a hundred adults, half of whom were bf and half of whom were ff, could you tell the difference? No thought not.
As for formula being made available on prescription, it would of course make people feel more sstigmatised than currently, because women, often vulnerable new mothers, would feel they needed to go to a professional to justify their decision to ff. And what would be the criteria for giving a prescription? Could a woman be refused a prescription for formula?