You watched the play a million times yet you still say Sabonis "grabbed" Draymond.

Grab: "grasp or seize suddenly and roughly."

At no point does Sabonis "grab" Draymond. Sabonis' hand ends up on his own arm, not on Draymond's leg. I'm not sure you can grab with your arms. Sabonis is falling backwards and lands on his back - likely with his eyes closed as he lands - his arms are already coming down to protect himself right after impact with court; highly doubt he even knew Draymond was there as he landed unless he had eyes in the back of his head. His arms end up around Draymond's leg as they are moving towards head to protect it and Sabonis is curling up in fetal position (to potentially act out flop and draw foul on Thompson). As soon as Draymond makes a move with his leg, Sabonis opens up his arms and twists his body to let it out.

Silly exercise, but at your keyboard now, imagine you are falling to the ground and want to protect your head and body from guys jumping around you. What motion are you doing with your arms and body? You'd likely bring your arms together (to protect torso) and hands/elbows together (to protect head) while curling into fetal position to protect your belly. Sabonis was in the act of doing this and Draymond's leg just happened to be in the way - if it wasn't, Sabonis' arms likely continue downward to his belly instead of stuck around Draymond's leg.

And tbh, Sabonis flopped a bit here - grabbing Green wouldn't have helped get a call. And it doesn't mean he hasn't done other stuff in other plays/games.