Yup. BU to take it out of context.
I don't use it, but I am in favour of the message - and even as a passionate bfer, would have given a friend suffering and on their knees the option of formula feeding if trying to continue to bf was making their life miserable and they were unable to cope. I'm not advocating chucking formula at someone whining about being up all night, but if a friend was on her knees after no sleep for months with a high needs baby who fed all the time, I'd be discussing with her what was best for them. And letting her know that it was okay - she doesn't need society's permission to ff. or mixed feed.
I'm definitely pro bf. I bfed the first 2 exclusively (and did ten mos on my knees with ds who fed 24/7 and couldn't take even a bottle of ebm as he was plastic averse due to hospitalization and weeks spent on a nebuliser at 3 mos). But if you can see it's destroying someone, then the maxim stands. If formula is what the mother needs to be able to function, then she deserves support, and enough trite comments to make her feel it is okay.
Dc3 was no born with no suck or gag reflex, and was tube fed and had to be regularly suctioned so that she didn't suffocate on regurgitated milk or her own saliva. I expressed for as long as possible. In my case it was more sane mummy, alive baby. It definitely cured me of my bf at all costs stance. Despite of course, the theoretical position that this vulnerable baby was the one who would benefit most of all from BM. 
Mental health issues in mothers of small babies and children are massive. You might not like the phrase (I don't either) but I fully support the maxim. Who cares if the baby is exclusively breast fed if the mother is on her knees weeping for most the day. In an ideal world, there would be enough support to make breast feeding a positive and enriching experience for all, but in rl that support is often limited to a few manly pats on the back and a 'this too shall pass'. No one is seriously offering to fetch up six times a night to hold her hand through the darkness and try and soothe the screaming baby. Every night for months on end. And if getting the dh to proffer an occasional bottle of formula gives a mother even half an hour respite, I'm all for it. And I might even break out the phrase.
On a slightly different note - my old manager used to say 'happy wife, happy life'.
Which made me want to kill her.