Are you a woman? Have you had children? Have you partnered a woman as your child and her cried through the night, both trying to make this “breastfeeding” thing work; both failing. “How can something so intrinsic to basic survival, be so hard!”. And yet it is.
Having a reflex and breastfeeding are two different things. The baby can have the reflex, but the mother has no milk or the latching technique is poor (as mentioned elsewhere in these comments). So the child not breastfeeding doesn't mean there is no reflex. And yes, the process can be painful and stressful to many mothers most especially first timers (experience also counts).
Talk confidently when you have experience.