Not your screen monkey (he/him)
This. I got chided once for revealing the ending of a 35 year old movie. I was not amused. If it’s been out 35 years, you’ve got no right to expect people to spoiler tag it for you.If the thread title says either "no spoilers" or "open spoilers", then act accordingly.
Otherwise, I take the view that there has to be a reasonable "statute of limitations" regarding spoilers - discussing Luke Skywalker's parentage is a very different proposition when walking past a line waiting to see the movie in 1980 than it is today.