Hey dude.
Ignore all the trolls. That Macbook can run WoW easily. This game is not hardware intensive at all.
Anyway, the Mac Client is hella buggy (as usual) and Blizzard is working on it: Crashing, freezing, and stuttering after 8.3 [Intel GPUs] - #556 by Drakuloth
Bottom line is: This is not your computer’s fault. Read the thread above for a couple of player solutions. Only Blizzard can fix the issue and that might take a while.
FWIW, I had the same problem on WoW Classic. Either: the game launched, after the loading screen it would crash my Macbook; or the game launched, I played for a while, the game would freeze and it would crash my Macbook. It got eventually fixed after a month but I think the issue is still there. Stopped playing in P2.