That's basically what leaving it blank does. Sadly disliking activities does nothing still since sims will just do those things still on their own but dislike doing it. They never should do it on their own if you set it to dislike.
I believe that was the intention, I remember specifically the devs sayins Sims should do the things they dislike much less.
I just hate leaving it blank because then when I switch households for awhile the places I leave blank often switch to like/dislike without my input so I thought if there was an actual neutral option the game would stop changing it
