here's why:

"It will give you a script which you need to add in the head part of your blog and it will start tracking all Keywords which drive traffic to your Blog/Website"

http://www.shoutmeloud.com/hittail-review-related-keyword-su...

Whenever I see uBlock flagging something, I always make sure to double-check as to what it actually is. In this case, it doesn't seem like HitTail is that malicious.