Sebastian Vettel, Carlos Sainz, Lance Stroll and Valtteri Bottas were all called to see the stewards after the race, and all received the same penalty.
A non-driving reprimand has some significance, because if any of the drivers receive two further driving-related reprimands within this season, they face a grid penalty.
Drivers are supposed to only wear T-shirts for the first part of the grid ceremonies, and remove them before the national anthem. They argued that in the busy, rainy conditions before the start they forgot to take them off.
The decision to penalise drivers for displaying messages has caused a stir on social media, but Masi is adamant that everyone has known the rules since the start of the 2021 season.
“Earlier this year we clarified,” he said. “And following discussion internally with the FIA and F1, we said we wanted to keep giving all of the drivers the ability to have the moment to show effectively their support for We Race as One however they chose to, but then the national anthem for a particular country should be respected with drivers all wearing their race suits.
“So it was clarified and made very clear that once that moment was displayed and the drivers showed their recognition they would have to remove their shirt or anything else they wore and go to the national anthem in their race uniform.
“And that’s been the same for a number of events now, so this is the first event where it has happened since and all of those drivers that kept their shirts on, so it wasn’t just Sebastian, there were four or five drivers, all received a non-driving reprimand for failing to follow the race director’s instructions.
“It was observed by a number of people including the media delegate whose out there. Myself on television. It went from me to the stewards, it was a breach and that’s why it was a reprimand for the first offence.”
Asked by Autosport if a reprimand that could help to trigger a grid penalty was too strong a punishment, Masi said: “You look at all penalties on the basis of what it is. Reprimands are the lowest penalty other than a warning, which really is not a penalty, it’s a warning.
“A non-driving reprimand, so you need to have two driving reprimands and one non-driving to ultimately get to a grid penalty. But as an example, three non-driving reprimands it doesn’t have that impact.”