To clarify a few points on
nipple confusion:
Some health care professionals don't believe it occurs. After working with hundreds, if not thousands of babies I am quite certain it does exist but the terminology is itself confusing. The baby is NOT confused. The baby wants to eat and it wants a method that works.
If the new mother/baby dyad are not yet skilled (breastfeeding is a LEARNED skill for mother and baby) in latching on effectively then obviously the bottle "works" more easily. If this rubber nipple option is presented early in the newborn's life, before s/he and the mother have had the time to learn effective breastfeeding the baby (and the mother) may come to prefer the artificial nipple, because it works. This is not confusion but that is the term commonly used.
If the new mother has short nipples the mother/infant dyad may have a slightly steeper learning curve on the way to effective breastfeeding. If the mother has longer and/or easily erected nipples the target is more obvious. The nipple serves mostly as a target. Functionally what is important is that the infant's tongue is placed far enough back on the maternal areola so that the infant can effectively lift and compress the milk out. This can work just fine with a shorter nipple, but the skill set the dyad need to locate the right zone may be more complex. Early use of an artificial nipple is more likely to cause problems if the mother has a less than obvious target. These are one of the types of dyads that are more likely to become "confused" if a rubber nipple is used before effective breastfeeding is learned.
Another part of the moving the milk from the mother to the baby dance is the active squirting of milk from the back of the breast forward to where the baby can more easily access it. This is called the let down reflex or the milk ejection reflex or MER. In the early days just after birth the MER is not as active as it will be later on. If any infant is exposed to the fast flowing and usually actively dripping bottle too early s/he doesn't learn it takes a short period of active suckling before milk flows with much volume. This is a flow preference, the baby says "I'd PREFER it to flow right now thank you", again not really confusion but again, that is the term most commonly used. This flow preference may happen to almost any infant who gets a bottle in the first few weeks of life. It is not such a problem later on. Once the mother's milk supply is abundant, the milk flows quickly. Early bottles also interfere with the mother developing an abundant milk supply because of the supply and demand nature of breastmilk regulation as well as undermining her confidence and delaying her acquisition of breastfeeding skills.
If you combine the flow preference with problems in learning the skills needed for effective breastfeeding you get "nipple confusion".
Health care professionals who deny the existence of this problem, regardless of the name applied may have based their belief structure on experiences with already skilled mothers who have obvious nipples, abundant milk supply and fast flowing MERs. It is the new and uncertain mother whose confidence is low and whose skills are as yet limited and who has short nipples and a frustrated baby that they should be looking at. It is also possible that they simply don't value breastfeeding and fall back to bottle feeding for every problem.
If artificial nipples are used with an older baby (usually after a month or so of effective breastfeeding) and the milk in the bottle is the mother's own milk (so the supply and demand regulation of breastmilk is not messed up) and the mother is now confident in her body and her skills the infant will usually not come to prefer the artificial nipple but will adapt fairly easily back and forth to the method offered at the moment.
A nursing strike is something different and I will node that as well as alternate feeding methods for the breastfed baby who has a need for supplementation separately.