Broadly, I think that if you read a thread of a game you aren't up to date with, then it's mostly on you. I'd like to think people would use spoilers as a courtesy to others with recent updates, but as I said, I'd consider that a courtesy, not a requirement.
That said, discussion of spoilers here with Cosy Cafe currently should be less to do with the first few days (the shy girl and the blonde girl) as the last update...OK. it seems most of us have seen and played it, but I don't think it's been released publicly yet, so there are, presumably, quite a number of people who haven't.
So if we're discussing spoiler use, then I think any discussion should be more about 'should we have been hiding away discussion on updates between their patreon release and their public release?'
Of course, if we did that, I imagine most of the last twenty(?) pages or so would be tagged that way, which seems...excessive.