Non humans as a whole. Of course you have opportunists and people who are sympathetic to their cause.However please note, that humans are also part of Scoia'tael in Gwent. Your description does not reflect "Gwent reality". At example there are Smugglers and Pavko Gale as Scoia'tael so it is not fitting your idea of "non human races band together".
ST are the rebels oppressed by the human kingdoms.