Why was Piastri penalised but Russell wasn't?

Oscar Piastri was penalized at Silverstone for similar actions to George Russell at Canada, both involved braking behind the safety car. The main difference was the wet weather and limited visibility at Silverstone. Piastri applied more brake pressure than Russell, resulting in a 10-second penalty, which some viewed as harsh. Teams and drivers advocate for consistent steward decisions in such incidents.