"It came out a long time ago" doesn't make spoilers ok

Just a quick rant.  I've often heard spoilers being justified on things that came out a long time ago, because they came out a long time ago.  But there are just so many tv shows, books, movies, games, etc that have been released over the years.  Even if you only count the classics.  There's so many that for any one work, no matter how old, there's always going to be many people who would like to have had experienced it but who haven't yet.