Seems Nobody cares, they have been reported countless times, the Admin / Owner barely is ever around I am thinking, doesn't really give a shit, just leaves teh forum up, 'As Is' - ie NOT his problem.
About the best you can do is, Ignore user, and when you sign in, in the morning and click new posts, look at by whom, read all the others and then mass click the 'read' tab and they go out of your active inventory. It sucks but that's about the best Ive found sofar.
In my forum, I have a few who can click a person to put them into a read only mode, for me to decide if they get perma shitcanned or not. Very rarely have to use it. One can also implement a double verify to get on the forum too, it takes a minute or two longer and yes it's a pain BUT it tends to make the bots go elsewhere, so can be taken down after a few days when they stop their shit.
Just foor for througt