Yeah I think this penalty is bullshit. Since both of them are on build laps, max is under no obligation to move over for Russell. As for Russell's argument that 'slow' cars should be off the racing line, no driver will drive off the racing line when there is no car on a hot lap to let through because it is dirty off line which will affect the tyre and ruin their tyre preparations.
This sets a dangerous precedent where cars behind will try to spook and bully cars ahead on build laps by rushing at them and making them either go faster and not get to prepare properly or go offline and pick up dust and rubber onto the tyre surface which again affects tyre preparations