Exclude Child Categories Using wp_list_categories

Question

Instead of excluding child categories, try to get only categories that have no parents (0)

    $cats = wp_list_categories( array(
        'parent' => 0
    ) );

That should work with no issues.

EDIT: get_the_category_list() does not support advanced arguments. Your best bet is wp_get_post_categories($post_id, array(‘parent=>0’)). That will return an array of objects, you have to do the HTML yourself with a foreach loop.