I’m not super sure that applies here - they aren’t being punished (legally) for getting the abortion, but for using the roads to get there. It seems to me conceptually similar to how European companies aren’t allowed to sell drugs that are used for lethal injection to the US, even though those drugs are legal to sell in Europe: They aren’t being punished for taking part in an execution that’s legal where it happens, just for doing something that enables it in a place where it isn’t legal. Same deal here.
I’m sure it’s an unconstitutional/illegal law for some other reason, I just don’t think this specific reason applies.