Sorry, but that’s simply not good advice. Nobody is born with perfect parenting skills and is granted all the answers. In fact, many parents are not fit to raise kids at all, others are simply overwhelmed and need help.
It’s very easy to have a kid, not particularly easy to raise one. The idea that all your decisions are magically correct and sound just because it’s your own kid and that every parent knows best is simply wrong. It’s healthy to doubt yourself and to ask for advice.
Also, parenting science is not quackery. This is an actively researched area and there are real scientific efforts to better understand child development with respect to biology, psychology and neuroscience. These efforts do lead to a better understanding of how kids can be raised and how certain parental decisions might affect a child.
Personally, I’m happy each time parents try to inform themselves and seek the advice of others. That doesn’t necessarily mean relying on the answers a bunch of strangers give on social media, but I hope the Fediverse as a whole can do better.
Right now, I can’t make the claims you did in your post initially.
You’re not causing permanent damage to a child by letting them sleep in your bed.
I wouldn’t know that. Intuitively, I do believe that co-sleeping would have a lot of benefits up to a certain age, after the infant stage and dangers of SIDS have passed. However, I could easily imagine that there might be adverse effects after a certain age. Would it be likely to occur after a handful of times? Probably not. Are there any indications on the threshold maybe? Anything to look out for, given the kid might have anything else going on? Maybe. All information I would have on that subject would indeed be anecdotal though, and so in turn pretty useless. Why the dismissal of an honest attempt at getting educated?
I would indeed argue for getting an overview of what science has to say on the matter and then making an individual, informedndecision based on all the additional context I’d have as a parent that I could never cram into a couple of posts on the internet.
Having access to scientific publications, I’ll see if I can provide some material later.
This is pretty much absolutely true by the way:
https://pubmed.ncbi.nlm.nih.gov/24785997/
Although, to be fair, that was done by Cutter Labs, which sure, had been acquired by Bayer, but to be honest, Cutter Labs was rotten from the start, they were also responsible for the Cutter incident, infecting people with Polio:
https://pmc.ncbi.nlm.nih.gov/articles/PMC1410842/