Not posting spoilers has rightfully become a genrally accepted net etiquette,
intended to minimise the risk of literally spoiling
a potential audiences enjoyment...

There are acccpted conventions for alerting the presence of spoliers in a forum thread title.

Nothing bizarre at all...

Unless you are one of those mean spirited folks who gets a spiteful kick
deliberately yelling out surprise character deaths and plot twists
loudly and on as many forums as possible...

Or arrogant shits on a power trip who write reviews for mainstream media...
[One of the worst spoilers I ever read was in the Radio Times..]

The age of War of the Worlds is immaterial,
not everyone has previously read or seen it...

..and on this forum, considering the average age and failing memory condition of membership,
many of us would not recall much about it anyway,
and will be coming to the new series with fresh virgin eyes and ears...

This is actuall one of the plus advantages of my mum's dementia..
She can enjoy the same movie several times over a couple of days,
and still not realise she has already seen it..

So in her extreme case, yeah... fair point.. spoilers don't matter...