And it is a bandwagon. I don’t doubt that there are some babies that are dairy or lactose intolerant but it would present itself quite clearly with rashes, bad bowel movements and bad vomit not regular baby vomit. But from experience, 90% of babies have colic/reflux in their first 3 months and are fussy and pretty miserable most of the time and the standard midwife/health visitor response is to switch to dairy free formula or cut dairy from diet if breastfeeding. Whereas in overwhelming majority of cases they just grow out of it by 12 weeks and meanwhile you should just eat all the chocolate and cheese you want to get you through it.