There's a difference between support and validation. This forum is also here to solicit honest opinions and feedback, even if it's not necessarily what the poster would like to hear. Everyone feels some form of that at 3 months, but that doesn't make it necessarily justifiable to prioritize baby-free outings over infant nutrition. If something makes you feel like shit, reevaluate, because a stranger's opinion isn't enough to actually make someone feel like shit unless there's a nugget of truth stored in it.
And this is where the judgement comes, anything other than breast milk is poor nutrition. Last I saw there were millions of babies thriving on formula so how anyone can say choosing it is risking infant nutrition is beyond me. Her baby will be fed a diet containing all the nutrition it needs, and so long as she doesn't spend the next fifteen years feeding chicken nuggets and chips, LO will grow up just fine. 3 months of breast milk has been a great start and is longer than many who are able, manage to go on for. How about being supportive and validating that at least
Last I saw, over 900 babies die in the states each year from being formula fed. I'm not trying to say that her baby is going to die, but there really is no point in pretending like they're of equal quality. Yes babies thrive on formula, but they also suffer from more frequent illness, ear infections, stomach bugs, etc. It's not always about whether they'll grow up "just fine", but it's about what they end up going through in the meantime, during that first year or two and whether it's really that much of a sacrifice on the mom's part to have to pause to pump (maybe) while she's out having fun during one year of her life (because this won't be an issue any other year unless she decides to have another) to justify risking those more frequent discomforts for her child. It
is a risk. That's a medical fact, not a judgement.