Not a psych, but got a PhD in related area and have lectured in Child Dev.
I think there's probably a happy medium whereby you can lengthen the periods of time a child is encouraged to settle themselves, until they get more used to doing this. Children are ready for this at different stages. Surprisingly, bedtimes for very young children can be later than you would think, to encourage them to sleep through once they are in bed. A friendly face around the door when there is distress reminds the child they have not been abandoned, as does people pottering about in the vicinity of the bedroom putting washing away or whatever while they are dropping off to sleep. We are essentially social beings, us humans.
So it's probably all about getting a balance between group membership and a degree of self-reliance, psychologically speaking, and different cultures come to this at different times. In the west we see our role as pushing our children away a bit from us and encouraging independence, in the east often parents perceive it as drawing children towards the extended group and improving their collective behaviour skills.
Hence there's no right or wrong answer to how to bring your child up, but the measure of success is probably the happiness, health and energy level evident within your own family. If any of these seem to be off kilter, then it makes sense to try alternative approaches until the situation is resolved to your satisfaction.
I don't think extreme positions are very helpful, nor do I think there is any virtue to buying opinionated baby books promoting inflexible positions towards child rearing. Parents need to be encouraged to try different things until they find the confidence to do what works for them. We all have the answers within us, but sometimes it just takes a bit of time to find them.