Hi Julien,
There are multiple ways to do it.
Here is one way(I just updated the above code)

function bpdev_exclude_users( $qs = false, $object = false ) {

	//if not members, let us return
	if ( $object != 'members' ) {
		return $qs;
	}

	$args = wp_parse_args($qs);
	//we are looking into friends list if the user id is given, do not hide here
	if ( ! empty( $args['user_id'] ) ) {
		return $qs;
	}

	$excluded_users = get_users( array(
		'role'      => 'administrator',
		'fields'    => 'ID'
	) );

	if ( ! empty( $args['exclude'] ) ) {

		if ( ! is_array( $args['exclude'] ) ) {
			$args['exclude'] = explode( ',', $args['exclude'] );
		}

		$args['exclude'] = array_merge( $args['exclude'], $excluded_users );

	} else {
		$args['exclude'] = $excluded_users;
	}

	$args['exclude'] = join(',', $args['exclude'] );

	$qs = build_query($args);

	return $qs;

}
add_action( 'bp_ajax_querystring','bpdev_exclude_users', 20, 2 );

Please put it in your bp-custom.php and all the admins will be invisible in the members directory.

Hope that helps.

Regards
Brajesh

Hi Julien,
Please add the following code to your bp-custom.php too

function buddydev_redirect_from_admin_profile() {
	//not a profile page or viewing own profile page,  no redirect
	if ( ! bp_is_user() || bp_is_my_profile() ) {
		return;
	}

	//check if the user is admin?
	//there are multiple ways to do it, I will show for Super admin
	//You can use user_can(bp_displayed_user_id(), 'cap_name' ) too, Make sure to change cap name to appropriate cap

	$redirect_url = site_url('/why-did-i-get-redirected');//or any url

	if ( is_super_admin( bp_displayed_user_id() ) ) {
		bp_core_redirect( $redirect_url );
	}

}

add_action( 'bp_template_redirect', 'buddydev_redirect_from_admin_profile' );

Change the redirect url as you please.

Hope that helps.

Regards
Brajesh

Thank you and have a great day to you too.

Regards
Brajesh