As a Brexiteer, I do think it rather strange of my fellow Brexiteers such as Farage and Johnson to call for Darroch's head when Brexiteers are supposed to believe in British sovereignty, not kowtowing to a foreign power like the US.
Yet on the other hand you can understand Leavers' frustrations with Darroch. It seems as though the Remainer British Establishment is trying to deliberately anger Trump to destroy any hopes of a post-Brexit trade agreement, which is the action of traitors.
When the Leavers finally take power later this month they should start to actively hunt down and severely punish any Remainers acting treasonably.