Sites with 50,000 users (ex: Woo Customers) cause browser to crash

I have a solution for this. I go in and hack the plugin file class-wp-import.php and change arguments in function author_select() when calling WP function wp_dropdown_users() by adding 'role' => 'administrator', to the list of arguments.

By doing this I can use the tool on large sites. It would be nice if this plugin excluded all customer and subscriber roles automatically, since one would never practically be assigning imported posts to them.