How is breastfeeding exclusively asking for a bad situation?
Then there's the auxillary effects that can be seen in OP's post -- since the baby is tied to Mom, it's Mom who has to defend against privacy/time intrusions. That's adding stress to what's already a tiring situation.
OP posted about a MIL problem- she certainly didn’t post asking about breastfeeding advise, it’s not a problem that needs to be fixed.
Well, technically OP was posting about a husband problem, not a MIL problem. If OP's husband was on the up and up this wouldn't be a problem because he could tell her no without "worrying about their feelings." Fixing the just-breastfeeding thing helps out with the husband problem. Also, TECHNICALLY OP was asking if she's the asshole, not asking for advice.
And you certainly are coming across as shaming her for her choices.
"Might be something you want to fix" is pointing out something that is causing them stress and is something that IS fixable, in most situations. It is in no way shape or form shaming.
Also, there's already plenty of shaming on the other side -- women who physically can't breastfeed or for whom it's a bad idea are shamed into doing it, even though it can be extremely painful already. In fact, one of the recommendations for breastfeeding hurting is APPLYING LEMON ON THE NIPPLE. That's right, more pain so the suckling pain doesn't feel so bad.
It's incredible that a small remark summing up to "hey you might want to add bottle to to your routine" is immediately taken as an attack.