Hi,
The comment system isn't meant to be used on the listings.
The vote_type is used to allow votes on vendors, not categories, at least for now.
So it's not easy to add that to the categories. It's not impossible, but it requires a developer to work on that.
Adding jcomments on the listings should be easy on the other hand.
You can add such code:
<?php
$comments = HIKASHOP_ROOT . 'components' . DS . 'com_jcomments' . DS . 'jcomments.php';
require_once ($comments);
echo JComments::showComments($this->element->category_id, 'com_hikashop', $this->element->category_name);
?>
in the file "listing" of the view "product" via the menu Display>Views and that should do it.