Because Rust is always out of position. He goes way too low in the OZ, letting his defender usually double team Crosby, and then makes the only available pass for 87 to the point. If it doesn't make it to the point, the other team is quickly going the other way while the Penguins have 3 players behind the net.
Yeah he's aggravating to watch. He always wants to be the 2nd guy into the corner, the 2nd guy to the net, etc. He scored a goal that way pickle stabbing after Zucker caused a scrum a couple weeks ago. But he needs to pick his spots a lot better. He just always does it without regard to whether he's the F3 or not.
I guess this is a combination of wanting to live up to the contract by scoring more (or trying to get a contract the last two years) and not wanting to take the physicality of being the first guy in. I don't know what's up with it, but it's losing hockey.
I think it's just less apparent when he plays with Geno because they get easier matchups, and they seem to usually have Petts and Petry behind them, and say what you want about Petts, he's our most positionally sound defender this year. Playing in front of Dumo and Letang all the time, like Sid's line does, magnifies the problem because Dumo isn't covering for Letang's adventurism as much anymore, and like last night, keeps making these mental errors and stupid 50/50 pinches.
If they want to run GCRust so badly, then stop putting Letang/Dumo behind them.