Irresponsible, yes, without question.
However I'm thinking it's #13's reaction to some foul moments earlier by #62 rider. #13 certainly accelerated with this dastardly trick in mind. #13 even looks back to gauge #62's reaction.
https://getyarn.io/yarn-clip/78a60ae...b-fbf765f9eb06

That he only tweaked the brake is kind. 6 piston 400mm rotor Brembo style brakes have incredible stopping power.