WordPress theme authors put spam website backlinks in their coding

Why do WordPress theme authors put spam website backlinks in their coding, and is there a safe way to remove it without affecting your website?
I just installed the Vantage theme, and when I check the source code on my webpage I can see an unwanted link to a website which has nothing to do with my website.

Here is the problem code:
<link rel=”profile” href=”https://gmpg.org/xfn/11&#8243; />
Why is this website: https://gmpg.org/xfn/11 with its blogs in my coding?

Problem: Why is this irrelevant foreign site link in the coding of my website and how do I remove it safely?
Here is he link to my site to view the source code:

https://www.megapixelrealestate.com/

Thanks for any help with this mystery,

Vanessa