Some days ago, I published a website so it is not a that popular. 5-6 days later, I saw that about 5% traffic is from hitleap.com, a traffic exchange service. Since it's not me doing this, I thought what is the guy who added my site in hitleap thinking? Does he want to 'help' me, or why would somebody do this?
No, whoever is doing it. He is not trying to help you. It may harm your AdSense account if you're using AdSense on your website. He is actually trying to get your Adsense account banned. You can contact - Hitleap Support and ask them to take your website off from their database.