The onus for avoiding spoilers is on the person who hasn't seen it not the person who has
Every time a new episode or movie comes out you've got the same mfs complaining about people discussing the show or film in the subreddit made for that thing. I get it I don't watch things straight away, I have a job and responsibilities too, so I actively avoid those spaces until I have. people excited for something and wanting to discuss it shouldn't have to not engage in discussion or share their excitement because someone hasn't been able to see it yet.
Also, spoiler tags are great. They should be used and I use them too. But expecting some sort of embargo after a movie or show comes out is ridiculous.