[Plugin: Content Slider by SlideDeck] impossible to desactivate slidedeck using functions.php

Hi all,
I tried to desactivate SlideDeck plugin using this code in functions.php file :

function site_init(){
	if (!is_admin()) {
		wp_deregister_script('slidedeck-library-js');
	}
}
add_action('init', 'site_init');

The function is executed but SlideDeck plugin is still registered in wp, style present in $GLOBALS[‘wp_scripts’] and style calling slidedeck js file.

This make me crazy.

https://www.ads-software.com/extend/plugins/slidedeck-lite-for-wordpress/