They usually make them drive an extra lap before the restart. It wouldn't be entirely fair to have them race starting on the same lap as the others without ever having done that lap.
So make them drive around the track until they're level. The red flag was a lengthy one anyway, adding another minute or so wouldn't have ruined anything, and skipping that completely ruined two races.
Fair point here > “Okay, it’s two of us today, but if 15 cars had damage and had to do what we did, are they going to start a race with 15 cars a lap down? I don’t think so. So I think they need to be a bit more open-minded. So that was frustrating.”
That's what happened to Ricciardo and Piastri, I thought they were just slow because of damage! Given that lapped cars are generally allowed to unlap themselves before a safety car restart, why wasn't this allowed for a red flag standing restart?
Because it wasn't a safety car restart. Inconsistent rule book. Obviously the rules for safety car restart and red flag restart should be the same, but currently they aren't.
I wonder if either team thought of this (and/or decided it was too risky and/or checked with race control and got an explicit 'no'):
After the formation-but-not-formation lap returning to the pits as everyone else took to the grid, then driving through and completing another lap while the grid was forming up.
IIRC during that lap the graphic said safety car, so I don't see why you couldn't drive through the pits and continue on as you could under a normal safety car.