Make WordPress process admin group comments using $allowedtags

kses_init is hooked onto the init hook with default priority, and (after first removing any of the kses filters) adds filters which strip out tags (wp_filter_post_kses for posts and wp_filter_kses for comments) if the user does not have the capability ‘unfiltered_html’.

Since the capability determines whether or not the user can post ‘unfiltered_html’ comments and posts – you probably don’t want to just remove that capability.

Instead, hook onto init, after kses_init, say with priority 20, and re-add the filters which strip out tags not in the $allowedtags whitelist:

add_action('init','wpse56687_filter_everyones_comments',20);
function wpse56687_filter_everyones_comments(){
      add_filter( 'pre_comment_content', 'wp_filter_kses' );
}