>>936339297 (OP)Some actually do. Kind of easy activity that they enjoy the reactions to the spam. This is especially true for gore spammer/ spiderman spammer as the frustration of their targets was the main purpose of the spamming itself.
Others, like one of our older days yotsuba chapter spammers, do it because they're physically sick and need a basic monotonous task to either help distract or merely chill out from their degree of pain. Other, like "Amnesiac" anon from a good while ago is an example of the monomaniacal side of that. Excessively and repetitiously posted details about their life just so they could recuperate from an additional amnesia from acute sleep deprivation from the pain of whatever they were dealing with or something like that. Sounded all schizo until they made a thread with a fuck load of photos.
Some, like the above, are just sick and literally got nothing else to do but post.
The rest I presume is because they, I dunno, lonely or extremely isolated. No socialisation can make people do the most bottom barrel stuff just to get some interaction.
The motivations behind repost bots though is usually more vindictive rather than pleasurable.