WordPress deletes users?!

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there are a lot of plugins 😐

Polylang: by Frédéric Demarle – 2.1
Advanced Custom Fields: Image Crop Add-on: by Anders Thorborg – 1.4.10
Advanced Custom Fields: Link: by Corey Worrell EMRL – 1.1.4
Admin Columns Pro: by AdminColumns.com – 3.8.9
Admin Menu Editor Pro: by Janis Elsts – 2.4.3
Advanced Cron Manager: by Kuba Mikita – 1.5
Advanced Custom Fields PRO: by Elliot Condon – 5.5.7
All 404 Redirect to Homepage: by Fakhri Alsadi – 1.7
Admin Columns – Advanced Custom Fields add-on: by Codepress – 1.3.5.2
Admin Columns – WooCommerce add-on: by Codepress – 1.4
Clean Image Filenames: by Upperdog – 1.1.1
Disable Users: by Jared Atchison – 1.0.5
Duplicate Post: by Enrico Battocchi – 3.1.2
Enable Media Replace: by Måns Jonasson – 3.0.5
Force Regenerate Thumbnails: by Pedro Elsner – 2.0.6
Formidable Bootstrap: by Strategy11 – 1.02
Formidable Polylang: by Strategy11 – 1.06
Formidable Registration: by Strategy11 – 1.11.09
Formidable Forms: by Strategy11 – 2.03.01
Google XML Sitemaps: by Arne Brachhold – 4.0.8
Imsanity: by Shane Bishop – 2.3.8
Language Fallback: by Bernhard Kau – 1.0.3
Loco Translate: by Tim Whitlock – 2.0.11
Media Library Assistant: by David Lingren Fair Trade Judaica – 2.41
Members: by Justin Tadlock – 1.1.3
Password Protected: by Ben Huson – 2.0.3
PAYMILL GmbH: by Matthias Reuter [email protected] – 1.11
Postman SMTP: by Jason Hendriks – 1.7.2
Simple Custom Post Order: by Sameer Humagain – 2.3
Simple History: by Pär Thernström – 2.13
Stop Spammers Spam Control: by Keith P. Graham – 6.15
UPS WooCommerce Shipping: by WooForce – 3.2.6
User Switching: by John Blackbourn – 1.0.9
Vendidero Helper: by Vendidero – 1.1.3
Hyyan WooCommerce Polylang Integration: by Hyyan Abo Fakher – 0.29.1
WooCommerce Customer Manager: by Ewout Fernhout – 1.2.5
WooCommerce Dynamic Pricing: by Lucas Stark – 2.12.2
WooCommerce Germanized Pro: by Vendidero – 1.6.2
WooCommerce Germanized: by Vendidero – 1.8.1
WooCommerce Sequential Order Numbers Pro: by WooThemes / SkyVerge – 1.10.1
WooCommerce: by WooThemes – 2.6.14
WooCommerce Helper: by WooCommerce – 1.7.2
WP Cerber: by Gregory – 4.1
WP Migrate DB Pro Media Files: by Delicious Brains – 1.4.7
WP Migrate DB Pro: by Delicious Brains – 1.7.1

of course i expected the deletion executed by wp cerber or stop spammers plugin. but i already asked and got answers from the plugin authors. they do not have a single line code which delete users.

i found this in woocommerce-germanized:
wp_schedule_event( time(), 'daily', 'woocommerce_gzd_customer_cleanup' );
and
add_action( 'woocommerce_gzd_customer_cleanup', array( $this, 'account_cleanup' ) );
and

public function account_cleanup() {
    
    if ( ! get_option( 'woocommerce_gzd_customer_cleanup_interval' ) || get_option( 'woocommerce_gzd_customer_cleanup_interval' ) == 0 )
        return;

    $user_query = new WP_User_Query(
        array( 'role' => 'Customer', 'meta_query' =>
            array(
                array(
                    'key'     => '_woocommerce_activation',
                    'compare' => 'EXISTS',
                ),
            ),
        )
    );

    if ( ! empty( $user_query->results ) ) {

        foreach ( $user_query->results as $user ) {

            // Check date interval
            $registered = $user->data->user_registered;
            $date_diff = WC_germanized()->get_date_diff( $registered, date( 'Y-m-d' ) );
            if ( $date_diff[ 'd' ] >= (int) get_option( 'woocommerce_gzd_customer_cleanup_interval' ) ) {
                require_once( ABSPATH . 'wp-admin/includes/user.php' );
                wp_delete_user( $user->ID );
            }
        }

    }
}

may this causes the issue? i have problems to understand whats going on here. it compares registration dates. maybe if someone does not complete the registration process, it gets deleted?!