I'm not sure what "experts" this article is referring to given that some paragraphs just cut off without making a point. They talk about the stress in the first week of nursery but don't clarify about later on. Of course any child will be stressed being away from their primary care giver even if it's to other family etc. That doesn't make it harmful long term.
I think you need to find more reputable sources of research than random bits you're finding online.
Ds goes to nursery 5 days a week. (We've no other option) and he absolutely loves it. He's become so much more social and confident with other people, he's learnt a lot and when he sees other children he just wants to go say hi now whereas before he would have watched from afar.
He's tired by the end of the day and I can tell he's had a big day so we have some quiet time, I feed him and he gets a snack and lots of closeness and cuddles when he's first in the door and he's happy to go do other things after about 5/10 mins. I don't really see this as different to an older child wanting to reconnect with their parent after a day apart learning and experiencing new things.
I feel like we're setting him up well for a nursery and then school environment and we've been very particular about the nursery we chose and feel their approach to things mirrors our values as parents so we are in alignment which will help ds with different boundaries in different places. He gets so excited when we pull into the car park that he now shouts yay! And starts kicking his feet. He cried at pick up and drop off the first two weeks and then it was like he realised he loves it!
@sociallydistained I work in child trauma and am very well versed in attachment theory - a child can have a perfectly healthy attachment to their care givers and be in nursery every day. Equally they can be with their caregiver 24/7 and have a very insecure attachment. Everything I've done to date as a parent has been with attachment theory in the back of my mind. Didn't worry for a second about sending ds to nursery. It sounds like you're taking it to the extreme - while I believe strongly in the value of attachment theory so much of it as social research isn't easily pinned down to specific scenarios as there are so many factors that go into it. I've also worked in nurseries and other early years settings, if best practice isn't happening then it needs to be called out just like it should be in a school, youth centre or other setting, it's incredibly unfair to scaremonger and make out that there aren't many wonderful safe nurseries that are that way because they have very dedicated and trained staff.