I made a little fix.
Instead of excluding forums in the admin panel, I changed it so you Include the forums that you select. That way if any new forums are created (with for example Buddypress groups) they will not appear.
It was really simple really. First you go into the plugin and edit bbpress.php
Then you are looking for the followin function:
function bbld_filter_forums()
In that function you can find this line:
$where = "AND ".$bbld_option['prefix']."topics.forum_id NOT IN ('$forum_ids')";
Replace with this:
$where = "AND ".$bbld_option['prefix']."topics.forum_id IN ('$forum_ids')";
Basically remove the "NOT". That's it.
And I think, Choosing forums to display rather than excluding might be a better option as defaults for this plugin.