Looks like there's nothing you can do about it, i expect its the same the "unwatch" feature in bitcointalk so threads will not show on your "Show new replies"
I have just posted the link of this topic to the chat, so let's see what is the official answer from Admin.
There is no reason to keep this disabled if there is option in backend to enabled it, and I am sure most members would not have anything against my suggestion.
Not as simple as turning it on from the backend; some features require a lot of time and money to implement; the ALT software is outdated and would require a lot of funds to improve things; and let us not forget that a lot of money were spent on the current BTT software; the admin here is patching everything around here on his own without much financial assistance.
If we want more features we need to start using the donation addresses more to support the admin and the forum.
You are absolutely right, I completely agree with but I highly doubt anybody will even consider using the donation address except the admin calls for it, not when people users are also after their own pockets and haven't gotten enough yet.
What I did suggest is that maybe it's time admin special thread in the forum discussion board where he will always announce whats the next feature he is working on, and through that, solicit for support from the forum users, I believe with this, alot of persons in campaign may be more willing to spare $10, $20 or more from their weekly pay to support the admin in improving the forum.