I didn't think the shove merited a penalty. That's light stick work, even in the regular season I'd be shocked if that was called.
However, that is clearly GI. You can't shove a defender into a goalie and then score, at least not by the rule book.
I always feel they have different people working different nights up in the review room in Toronto and some of them interpret GI differently than the other people that get the alternate shifts. As much wording as they try to put in to prevent a judgement call, that's exactly what it boils down to. They exercise so much resource into making sure offside/onside is black and white but with something far more important like GI, it all depends on who's working that night.