Easiest way is to not click on the thread. Another useful tip is to purchase a mouse with a scroll wheel.
May I ask why this bothers you? Not the concept of this competition but how is this thread such an annoyance that it would compel you to make such a statement rather than just manually ignore the thread? It's just a line on a screen in an index on Demonland and not flooding your timeline on Facebook or Twitter.
Another date has been added to the official site.
Upcoming Men's Training Sessions
Date: Monday, 18 February
Session start time: 9.30am
Location: Gosch's Paddock, Olympic Bvd, Melbourne
http://melbournefc.com.au/Team/training-times