Spoilers

Background to this particular hobby horse.

So you work in an environment where people have time to talk while they work.
Two of the employees don't have to commute to work and are able to habitually go to see every new film on the evening of the day that it opens.
They share an apartment and can talk anytime ! 
Those two employees then come to work and discuss in detail all of the ins and outs of these new films.
Nothing  anyone says can stop this activity and "management" finds it too small a problem to deal with these two senior employees.
You come to loath people who deliberately and maliciously spoil films for others.

Ok, so, it's years later. 
You encounter someone on a  message board who insists on "telling the twist" or "telling the ending" and no matter how many times he/she has been asked to stop, insists on doing it. He/she has been told by people who seem to like him/her how to use the but absolutely refuses to do so and has even taken to starting threads seemingly with the sole purpose of "telling all".  

So....  Malicious ?  Clueless? Impaired brain function?  

Encountered any such "spoilers" on or off-line  ? How did you deal with them?

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I know tl:dr !   

Taking my soapbox with me when I go !