When DD1 smacked her lips and mumbled in her sleep it woke me, by the time she was making any noise that could be considered unhappy she was in my arms and my boob was out. No crying.
DD2 was the same, I never waited until mine were crying before I fed them, I heard/saw the feeding cues and acted on them before they were upset and hungry enough to wail.
However, DD2 did cry quite a lot in her first 8 or 9 weeks. She is intolerant to cows milk protein, and had horrific reflux and colic and used to cry and cry in the evenings, cluster-feeding and wailing for three or four hours. Once we figured out the cause of the reflux and colic and cut cows milk/dairy out of my diet she became a settled happy baby and no longer cried for any length of time.
My point here is that babies don't cry for no reason. There is always a cause, sometimes we figure out the cause, other times we don't, and eventually the crying stops when they get older any way.
And whilst my view may be based on one persons experience (my own), it is not just based on my children. I worked as a nanny for several years and have been working in Radiology for nearly a decade, and in this time have cared for many babies, and I am sure that no baby cries for fun, or to exercise their lungs. They are always expressing something, it may not always be possible to figure out what they are trying to tell us, or be willing or able to give them what they are asking for (even if that is just to not be left alone in the dark ) but they are always communicating in the only way they know how to.
Really, truly, honestly, I think the parents of the baby being discussed in the OP are very selfish and thoughtless. Both towards their baby and their neighbours, and ideally something should be said to them so that they stop a course of action that is both dangerous and distressing.
But of course, I am being unreasonable, and talking shite.......