Working together for the good of the country is the lamest excuse not to hold those in power liable for their actions ever devised and one of the most widely used too. Supporting the government that brought about Brexit and made it extra bad for the country is as much working together for the good of the country as supporting Trump in his antics is working for the good of the country.
It's especially true when May and her merry band can offer not one positive scenario for Brexit. Being willing to embrace a hard Brexit is not working for the good of the country, that should be the point where they admit they can't get the magical deal they promised during the referendum campaign and look to see how they can back out of this whole sorry process.