Elisabeth Petrucelli puts forward her insights into exclusively pumping in this excellent blog post.
I can only add but a shred more.
The fact that the data does not exist to show that BF is 'better' than EP shows how our culture has become obsessed that the biological norm needs to prove itself against the many interventions put upon breastfeeding. BF is the biological norm and as such, there is no need to provide evidence that it is 'superior'. It is just the norm. Not better, not superior. Evidence to show how it differs from EP is a nice scientific extra for people to be all academic about but it isn't necessary to prove that the way mammals are designed to eat is the normal way to eat and all other methods are not quite equal to the norm.
For me EPing has nothing to prove either. In the absence of breastfeeding, mothers own milk, expressed, is the next logical option. Breastfeeding is worth fighting for just like learning to walk without a crutch is worth fighting for. The medical and wider community provide multiple means of support to get people walking unaided but they don't provide multiple systems of support for breastfeeding when it isn't going well. Put another way, no one would dream of telling someone that she doesn't have time to help you to learn to walk so here is a crutch. It is just as good. Likewise, why is it ok to tell a mum that we don't have the time to teach her to breastfeed; here is a pump. Mothers and their babies lose out. Mothers are trying to source robust breastfeeding support when they are at their most vulnerable. The lottery of support available leads to much disappointment for many and a source of much grief and emotional pain.
My last point comes to the widely held misconception mentioned in the original article that exclusively pumping mothers cannot benefit from breastfeeding support! What a travesty! They are using their breasts to feed their babies!!! Hello?
Lactation consultants who are turning EP mothers away from lactation support really must reflect on the WHO Code and the UNICEF Baby Friendly Initiative as well as their own education and workplace practice. This is a whole new post on its own and unfortunately, real life is calling at the moment.