To limit your hidden filters to a specific directory, you can use this code:
add_filter ('bps_hidden_filters', 'my_hidden_filters');
function my_hidden_filters ($filters)
if (!is_page('Page Title')) return $filters;
// add your hidden filters for 'Page Title' here
Replace ‘Page Title’ with the actual title of the page where you put the [bps_directory] shortcode.
By the way, the code you posted adds the filter only if the current user has a non-empty value in his/her own profile. Is that what you need?