This is enabled through the:
1. Communities>special events>friends asking friends>Kintera Thon
2. Hover over the event name and select Website info
3. Then from the website info checklist select website features
4. Within the website features section scroll down the page to the events social media section
5. The options for each social media Facebook enter a Comments title or select to hide comments  

For any questions Chat with Support and reference this article.