My first thought was "Have Paddy Power suddenly started employing Peter Tatchell?, are they trying on Out someone"
But having done a bit of background research it appears that this is a joint campaign with Stonewall and backed by none other than Joey Barton! The famously happy go lucky cheeky chappy.
The main criticism that the campaign has drawn is the strapline "right behind gay footballers", which is seen by some as a bit "Carry On football"