WP 4.5 hide core customizer sections

If you check out the source of WP_Customizer, you’ll see there is no title_tagline or header_image at the time the filter runs:

final class WP_Customize_Manager {
    protected $components = array( 'widgets', 'nav_menus' );

    public function __construct() {
        // a bunch of requires

        $components = apply_filters( 'customize_loaded_components', $this->components, $this );
    }
}

Use the customize_register hook to remove the sections after WP has added them:

function wpse_225164_remove_core_sections( $wp_customize ) {
    $wp_customize->remove_section( 'title_tagline' );
    $wp_customize->remove_section( 'header_image' );
}

add_action( 'customize_register', 'wpse_225164_remove_core_sections' );