Sleep is an emotive issue. However,the fact that books with routines which have helped thousands of people should not be removed or criticised because other people feel the fact they choose not to follow them, makes them feel they are doing it all wrong.
There are books about all kinds of parenting methods. I have seen the ones about co sleeping and it's benefits. I have chosen not to do that, but I accept other people want to. It does not make me feel bad. I just see that the approach co-sleepers take is not for me.
Parenting is something which seems to make people feel guilty at every turn. We can feel guilty for formula feeding, for following g a routine, for not following a routine, for working, for using childcare, for weaning early or late, for not doing baby led weaning, for letting our child cry, for using a bottle too long, for using a dummy, for not using a dummy etc etc. and there are books about all of these, but people just have to cope and find their own way.
So if people decide they will get more sleep by feeding their baby to sleep, driving them along the motorway or rocking them to sleep, then that is fine. They can do it. However, other people don't want to do those things, but put their baby into bed at whatever time and see them again in the morning. That is fine too.
As to whether waking frequently in the night prevents a baby being contented...well I think it depends on age. All tiny babies wake and feed and wake and feed. It doesn't stop them being contented. It is different for a 6 year old at school, who needs to be able to concentrate in order to learn and to interact well with their peers and teachers. They probably would not describe themselves as not content, and clearly the occasional night waking is not the same as constant waking through the night. However, there is certainly a point when a lack of sleep has a negative effect on children, but I dont think it is at the baby stage.
I think we have to make our choices and be comfortable with them. There might always be people who eat better, behave better, sleep better than our children. People will adopt different approaches to the ones we choose. But if we are happy with our choices and the outcomes of them, that is all that matters, and we just have to live with seeing other people having different consequences because they made different choices.