For a lot of people just about every aspect of adult life sucks. You cant afford anything, your job is stressful as hell, everywhere you go costs money, your responsible for your own healthcare, etc.

It's not weird at all to be nostalgic about your childhood where you were happy, loved, and carefree (if you were fortunate enough to have had a childhood like that).

I think it's just different people being in different places in their lives. For some people the stability and safety of the childhood home isn't something they've replicated elsewhere yet, so the nostalgia is all they really have left of that feeling.

Even then they might not want to go back, but just be acutely feeling an absence of that type of security.

I'm sort of in the middle. I have a safe, stable and comfortable environment, and I'm doing my best to preserve that for my kids. I can also remember the feeling of childhood familiarity and just knowing how things will be, and not having the responsibility to keep that stability be mine. And that's a comfortable blanket.
Not one I would want to live in, but having lost both my parents I do wish I could pull that blanket over my lap for a bit every once in a while.

Normal feelings. I had a decent childhood. My parents fought all the time but nothing beyond that. Still don't want to be in my childhood kitchen forever.