Because when nothing was happening it was not very threatening but now we want to ally with them. They have done lots of things to Skaikru in the past. Skaikru has done lots of things to them as well but people like this think that's okay because to them the Trikru started the fight. They don't think about how when Skaikru came down they looked like Mountain Men except they didn't have to stay inside the mountain, they just walked around with guns breaking laws. They just think that when we are allied, Trikru will be able to build up their army ready to attack us again and we won't be able to do anything to stop them without looking bad and making everyone attack us. They didn't even know alliance was possible before.